What each character is grounded in.

Each of the six historical figures in Valoquent is grounded in a set of public-domain texts. Their own writing where it exists, the most credible biographies and primary accounts where it doesn't. This page lists every source by character, with edition, license, and reliability notes. None of it is opaque. None of it is invented.

28 source works 6 characters ~1.3M words All public domain Last reviewed May 2026

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Marcus Aurelius Marie Curie Frederick Douglass Albert Einstein Leonardo da Vinci Cleopatra VII
I.

Marcus Aurelius

121 to 180 AD · Roman emperor and Stoic philosopher

The Meditations are the spine. They are Marcus's own voice, written privately, never intended for publication. Cassius Dio's account of his reign provides the exterior life the Meditations leave out.

2 source works ~81,000 words 1 primary, 1 contemporary historical
01
Meditations
Marcus Aurelius · written c. 161 to 180 AD Primary Philosophy Voice

Marcus's private journals. The text covers Stoic philosophy in practice: duty, virtue, acceptance, self-discipline, the nature of time and death, the inner citadel, leadership in service of the common good, and his own self-criticism in trying to live up to his ideals.

The included scholarly introduction covers his life and reign. Public domain edition, Project Gutenberg.

What this grounds

The character's philosophical core and his measured, reflective speech pattern. The Meditations are how Marcus actually sounds when he is being honest with himself.

Read on Project Gutenberg
02
Roman History, Books 71 to 72 (the reign of Marcus)
Cassius Dio · Foster translation, 1906 Contemporary historical Reign

Cassius Dio's account of Marcus's reign as emperor. Covers the Marcomannic Wars on the Danube, the Antonine Plague, his co-emperor Lucius Verus, the rebellion of Cassius and Marcus's merciful response, military campaigns and troop relations, the succession decision that produced Commodus, and his death in 180 AD.

What this grounds

The exterior life. The Meditations are interior philosophy. Dio is what Marcus actually did. Essential for the character to discuss his reign as ruler, not only his life as a philosopher, and to discuss the gap between his ideals and the realities of imperial governance.

Read on Project Gutenberg
II.

Marie Curie

1867 to 1934 · physicist and chemist, two-time Nobel laureate

Marie's own writing carries the voice. Her doctoral thesis carries the science. The Eve Curie biography fills the personal and emotional dimensions that Marie herself would never have written about.

4 source works ~251,000 words 3 primary, 1 family biography
03
Pierre Curie, with autobiographical notes
Marie Curie · written after Pierre's death, English edition 1923 Primary Voice Partnership

Marie's biography of Pierre, with autobiographical notes covering her own childhood and education in Poland. Tells the radium story through the partnership: the shed laboratory, years of manual labor, the philosophy of pure research, the French academic establishment and its barriers to women.

What this grounds

Marie's authentic first-person voice. The tone is precise, measured, emotionally restrained but deeply felt. This is the source for grounding the character's speech patterns and emotional register.

Read on Project Gutenberg
04
Radioactive Substances (doctoral thesis)
Marie Curie · Sorbonne, 1903 · English translation 1904 Primary Science

The doctoral thesis on radioactivity. Systematic study of radium, polonium, uranium, and thorium. Measurement methodology with the electrometer, quantitative analysis of radioactive elements, chemical separation and purification methods, emanation and half-life, and the theoretical implications for atomic structure.

What this grounds

The scientific foundation in Marie's own voice. Where the biographical sources tell the story of radium's discovery, the thesis shows the experimental rigor and precision behind it. The grounding source when conversation turns to the actual science.

Read on Project Gutenberg
05
The Discovery of Radium, address at Vassar College
Marie Curie · public lecture, May 1921 Primary Discovery narrative

Marie's 1921 public lecture at Vassar. A rare direct account: how radium was isolated, the shed laboratory, the years of perseverance, the moment of discovery, Pierre's partnership, and her refusal to patent radium because "research belongs to all humanity."

What this grounds

Marie's own voice telling the discovery story. Most of her public appearances were ceremonial. This is one of the few sustained public speeches she gave. Especially important for grounding her values around scientific freedom and her refusal of profit.

Read on Project Gutenberg
06
Madame Curie
Eve Curie · 1937, US public domain edition Family biography Life narrative

Marie's daughter Eve Curie's biography of her mother. Covers Marie's childhood in Russian-occupied Poland, near-starvation as a student in Paris, the meeting and courtship with Pierre, the Nobel Prize years, Pierre's death by horse cart, the World War I mobile X-ray units she drove to the front, the Langevin scandal, the American tours, and her final years of declining health from radiation exposure.

What this grounds

Full biographical coverage from a daughter who knew her intimately. Where the Pierre Curie biography gives Marie's own voice on the science, this fills the personal and emotional dimensions Marie would never have written about herself: childhood, WWI service, the scandal, the late-life suffering.

Read on Internet Archive
III.

Frederick Douglass

1818 to 1895 · abolitionist, statesman, writer, orator

Douglass is the only character grounded entirely in his own first-person writing. Three autobiographies across fifty years of his life, from his 1845 Narrative to the full Life and Times. All Douglass, all the way through.

3 source works ~306,000 words 3 primary autobiographies
07
Narrative of the Life of Frederick Douglass, an American Slave
Frederick Douglass · 1845 Primary Slavery Voice

The first and most concentrated autobiography. Written in 1845, soon after his escape. Slavery firsthand: daily life, brutality, learning to read in secret, the psychological corruption slavery inflicts on slaveholders, and the escape from Baltimore (kept deliberately vague to protect the network).

What this grounds

The fire of the young Douglass. The rhetorical power, the urgency, the unflinching moral clarity of a man who has just escaped bondage. This is the source for the character's moral authority and rhetorical force.

Read on Project Gutenberg
08
My Bondage and My Freedom (key chapters)
Frederick Douglass · 1855 Primary Reflection

The second autobiography, written ten years later with more distance and analysis. Expanded detail on his grandmother's cabin, Sophia Auld teaching him letters and then being forbidden, the fight with Covey as a psychological turning point, escape planning and betrayal, and a more sophisticated analysis of slavery as a system rather than only a set of cruelties.

What this grounds

The reflective Douglass. The voice of a man who has had a decade to think about what happened to him and what slavery does to a society. The character's analytical depth on race in America comes from here.

Read on Project Gutenberg
09
Life and Times of Frederick Douglass
Frederick Douglass · 1881, expanded 1892 Primary Politics Reconstruction

The complete autobiography. Covers the abolitionist movement, his friendship and tensions with William Lloyd Garrison, his relationship with John Brown and Harpers Ferry, meeting Lincoln, recruiting the 54th Massachusetts, Reconstruction's hopes and betrayals, his political career as U.S. Marshal and Recorder of Deeds, his service as Minister to Haiti, and his second marriage to Helen Pitts and the public backlash that followed.

What this grounds

Everything after escape. The other two autobiographies are about slavery and freedom. Life and Times is about what he did with the fifty years that followed. Essential for the character to discuss the Civil War, Lincoln, Reconstruction, and late-life reflection.

Read on Project Gutenberg
IV.

Albert Einstein

1879 to 1955 · theoretical physicist

The 1905 annus mirabilis papers are the spine. The 1922 Princeton lectures show his mature physics. The Swiss Patent Office record, the Britannica entry, and the Szilard-Roosevelt letter add institutional and political dimensions. One biographical source is included with an explicit reliability caveat.

9 source works ~188,000 words 7 primary, 1 biography, 1 reference
10
On the Electrodynamics of Moving Bodies (Special Relativity, 1905)
Albert Einstein · Annalen der Physik · 1905 Primary Physics

The 1905 paper that revolutionized physics. The original derivation of special relativity: Lorentz transformations, the relativity principle, the absolute versus relative nature of simultaneity, time dilation, length contraction, and the transformation of electromagnetic fields between moving reference frames.

What this grounds

Einstein's original technical thinking on relativity, before he had spent decades simplifying it for the public. The grounding source when the conversation goes deeper than the popular explanations.

Read on Wikisource
11
Does the Inertia of a Body Depend Upon Its Energy-Content? (E=mc², 1905)
Albert Einstein · Annalen der Physik · 1905 Primary Physics

The short 1905 paper that introduced mass-energy equivalence. The original derivation of E=mc² in Einstein's own words, energy content of bodies, and the implications for the relationship between matter and radiation.

What this grounds

The foundational source for the most famous equation in physics. When the character is asked about E=mc², he can answer from his own original derivation rather than the secondhand summaries that came later.

Read on Wikisource
12
Investigations on the Theory of Brownian Movement (1905)
Albert Einstein · Annalen der Physik · 1905 · Dover edition Primary Physics

The third of the 1905 annus mirabilis papers. Theory of Brownian motion, molecular-kinetic explanation, statistical mechanics, and the experimental validation of the atomic hypothesis through measurable particle motion. The work the Nobel Prize was actually awarded for.

What this grounds

The work that proved atoms exist. When the character is asked about his Nobel Prize, statistical mechanics, or his contributions outside relativity, this is the grounding source.

Read on Project Gutenberg
13
Relativity: The Special and General Theory
Albert Einstein · 1916, English edition 1920 Primary Pedagogy

Einstein's own popular exposition of relativity, written for the educated lay reader. Special relativity, general relativity, curved spacetime, gravity as geometry, and the thought experiments he used to teach the theory. Short sentences, concrete analogies, building from simple premises.

What this grounds

Einstein's pedagogical voice. This is how he sounds when he is teaching, not when he is publishing. The source for the character's accessible, thought-experiment-heavy explanatory style.

Read on Project Gutenberg
14
The Meaning of Relativity (Princeton lectures, 1921)
Albert Einstein · Princeton University · 1921, published 1922 Primary Physics Philosophy

Einstein's 1921 Princeton lectures, four lectures unifying special and general relativity at mid-level rigor. Spacetime and non-Euclidean geometry, gravity as curved spacetime, tensor calculus, cosmology, the principle of equivalence, and the relationship between physical reality and mathematical description.

What this grounds

The bridge between the technical 1905 papers and his philosophical writings. When the conversation needs both rigor and meaning, this is the source.

Read on Project Gutenberg
15
Sidelights on Relativity (Leiden and Berlin addresses)
Albert Einstein · public addresses 1920 to 1921 Primary Philosophy of science

Two complete public addresses. "Ether and the Theory of Relativity" (1920 Leiden) covers the history of the ether concept and the philosophical shift from mechanical to field-based physics. "Geometry and Experience" (1921 Berlin) covers the relationship between mathematics and physical reality.

What this grounds

Einstein's voice on the philosophy of science: what science is, how it relates to reality, the tension between mathematical elegance and empirical truth. Essential when the conversation turns from physics to what physics means.

Read on Project Gutenberg
16
Einstein-Szilard letter to President Roosevelt
Einstein and Szilard · August 2, 1939 Primary Policy Bomb and conscience

The letter Einstein co-signed warning Roosevelt that nuclear chain reactions in uranium could produce a weapon, and that Germany was likely pursuing it. The document that catalyzed the Manhattan Project.

What this grounds

The political and moral pivot in Einstein's life. The character's grief, conscience, and famous regret ("If I had known, I would have become a watchmaker") all anchor to this document. Essential for any conversation about the bomb.

Read on Wikisource
17
Encyclopædia Britannica entry, 1922 edition
F.A. Lindemann · Britannica 1922 Contemporary reference

A short biographical entry written by F.A. Lindemann in 1922. Useful for dating milestones (Patent Office years, Berlin appointment, Nobel citation for the photoelectric effect rather than relativity) and for understanding how Einstein was viewed in real time by the scientific establishment.

What this grounds

Quick biographical reference and historical context. Useful for the character to discuss how he was understood by his contemporaries while he was alive.

Read on Wikisource
18
Swiss Patent Office record, Bern (1902 to 1909)
Swiss Federal Institute of Intellectual Property Government archive

The Swiss IPI's institutional record of Einstein's patent examiner years. Friedrich Haller as director, Einstein's own description of patent review as a "cobbler's trade," Room 86, and the institutional context of his annus mirabilis years.

What this grounds

The Patent Office period. A formative time in Einstein's career, often mentioned in summary but rarely documented in detail. The character can speak about Bern from the institutional record itself.

View on Swiss IPI
19
Einstein, the Searcher
Alexander Moszkowski · Methuen, 1921 · Brose translation Contemporary biography Reliability caveat

Based on personal conversations between Berlin journalist Alexander Moszkowski and Einstein during 1919 to 1921. Covers Einstein's childhood (the compass story, Munich, slow speech development), his views on great scientists, education reform, multi-dimensional space, and the creative act of discovery. Most importantly, it captures his humor, warmth, and conversational style in a way no other public-domain source does.

Reliability note

Einstein later criticized this book as embarrassing and inaccurate in places. Moszkowski was a journalist and humorist, not a physicist. The character uses this source for personality, speech patterns, humor, and conversational voice. Specific scientific or biographical claims are cross-checked against Einstein's own papers before being treated as ground truth.

What this grounds

The human side of Einstein. Personality, humor, conversational rhythm. The only public-domain source that captures these dimensions in his own time.

Read on Project Gutenberg
Coverage notes Einstein's post-1927 personal writings ("The World As I See It," "Out of My Later Years") remain under copyright and are not in the grounding library. The Moszkowski biography partially fills the personal life gap with the reliability caveat above. The full text of the photoelectric effect paper is not in the grounding library, though the Britannica entry references it.
V.

Leonardo da Vinci

1452 to 1519 · painter, engineer, anatomist, polymath

Leonardo's own notebooks form the spine: six thematic collections covering his art, science, engineering, anatomy, philosophy, and personal letters. Vasari, Pater, and Brockwell fill in the biography and the famous stories the notebooks don't contain.

9 source works ~268,000 words 6 primary notebooks, 3 biographical
20
Notebooks: Painting, Light, and Color
Leonardo da Vinci · written 1480s to 1510s · Richter compilation 1888 Primary Art theory

Theory of light, shadow, and color in painting. Optical phenomena, the perspective of color, atmospheric effects, the science of seeing, chiaroscuro technique grounded in physics.

What this grounds

Leonardo's artistic theory and the way he talks about seeing.

Read on Project Gutenberg
21
Notebooks: Practice of Painting
Leonardo da Vinci · Richter compilation 1888 Primary Craft

Practical painting instruction. Proportions, composition, technique. How to depict figures, emotions, and movement. Studio practice and workshop methods. Critiques of other painters and common errors.

What this grounds

The craftsman's voice. Leonardo discussing the nuts and bolts of making art, in his didactic teaching register.

Read on Project Gutenberg
22
Notebooks: Philosophy, Science, and Personal Letters
Leonardo da Vinci · Richter compilation 1888 Primary Personality Voice

Philosophy of knowledge: experience versus authority, science versus dogma. Observations on human nature and society. Astronomy, geology, physics. Personal letters and professional correspondence. Humor, fables, riddles, the famous "misers" and "complaints" passages where Leonardo is frustrated.

What this grounds

Leonardo's inner life. This is the most personal section: opinions, humor, frustrations. Critical for the character to read as a complete person rather than only a polymath myth.

Read on Project Gutenberg
23
Notebooks: Architecture and Engineering
Leonardo da Vinci · Richter compilation 1888 Primary Engineering

Architectural designs (churches, ideal cities, fortifications), engineering (canals, bridges, hydraulic machines, military devices), the famous flying machine designs, water management, and his vision for Milan's reconstruction.

What this grounds

Leonardo the engineer and inventor. The grounding source for conversations about machines, water, fortification, and the relationship between beauty and function.

Read on Project Gutenberg
24
Notebooks: Anatomy and Proportions
Leonardo da Vinci · Richter compilation 1888 Primary Anatomy

Human anatomy from dissection: muscles, bones, organs. The Vitruvian Man and human proportions. Comparative anatomy across humans and animals. The body as machine.

What this grounds

Leonardo the anatomist. A distinctive and memorable aspect of his character, including his unusual relationship with the dead and dissection.

Read on Project Gutenberg
25
Notebooks: Botany and Landscape
Leonardo da Vinci · Richter compilation 1888 Primary Nature

Botanical observation (tree growth, leaf arrangement, plant movement) and landscape painting (mountains, water, weather, atmosphere). The science of representing nature accurately.

What this grounds

Leonardo's connection to the natural world. Patient, detailed observation as both science and art.

Read on Project Gutenberg
26
Leonardo da Vinci (biography)
Maurice W. Brockwell · Methuen, 1908 Biography

Chronological biography from birth in Vinci through death in France. Verrocchio apprenticeship, the first Milan period and The Last Supper, the Mona Lisa, the Michelangelo rivalry, the Roman period, the final years in France under Francis I. Personality notes on restlessness, perfectionism, and his pattern of abandoning projects.

What this grounds

Biographical scaffolding. The Notebooks give Leonardo's own thoughts but almost no life narrative. This connects the dots: who he worked for, where he lived, what happened to him.

Read on Project Gutenberg
27
Lives of the Most Eminent Painters, Sculptors and Architects (Leonardo chapter)
Giorgio Vasari · 1568 · de Vere translation 1912 Renaissance biography

The chapter on Leonardo from Vasari's Lives. The primary source for most of the famous Leonardo stories: the Verrocchio apprenticeship and the angel that surpassed the master, the Mona Lisa with musicians keeping her smiling, the search through Milan's streets for the face of Judas, the rivalry with Michelangelo, the vegetarianism and the freed birds, the death in the king's arms.

What this grounds

The biographical stories everyone knows about Leonardo, but that the Notebooks don't contain. Fills the biggest personal-life gap.

Read on Project Gutenberg
28
The Renaissance: Studies in Art and Poetry (Leonardo essay)
Walter Pater · 1873 Aesthetic interpretation

Pater's famous essay on Leonardo. Aesthetic interpretation rather than biography: the three periods of his life (Florence, Milan, wandering), his aesthetic philosophy, the Mona Lisa's enigmatic smile, his contemporaries' view of him as "possessor of some unsanctified wisdom," and the cultural reasons Leonardo continues to fascinate.

What this grounds

Psychological and aesthetic depth. Vasari gives the facts, the Notebooks give Leonardo's own thoughts, Pater gives the interpretation: what made Leonardo Leonardo. Useful when conversations turn to creativity, beauty, or meaning.

Read on Project Gutenberg
Coverage notes Specific masterwork provenance details (Mona Lisa commission history, Last Supper deterioration), the 1476 sodomy charge, the detailed Salai relationship, and French court politics are not deeply covered in the grounding library. The character is most reliable on the topics the Notebooks cover and on the events Vasari and Brockwell describe.
VI.

Cleopatra VII

69 to 30 BC · last pharaoh of Ptolemaic Egypt

No primary writing by Cleopatra survives. Her grounding comes from the Roman historians who shaped her image (Plutarch and Suetonius) and from a full biography written by an Egyptologist with deep knowledge of Ptolemaic Alexandria (Weigall). The Roman and Egyptian perspectives are both in the grounding library, which lets the character engage with how she was framed against how she lived.

3 source works ~221,000 words 2 ancient Roman historians, 1 modern Egyptologist
29
Life of Antony (from Plutarch's Lives)
Plutarch · written c. 110 AD · Dryden translation Ancient historian Roman perspective

The most vivid ancient account of Cleopatra and Antony. The barge on the Cydnus, her multilingualism, the Donations of Alexandria, the Battle of Actium and its aftermath, Antony's decline and death, Cleopatra's own death and final defiance. The source Shakespeare drew on.

What this grounds

The primary dramatic source for Cleopatra's most famous years (41 to 30 BC).

Read on Project Gutenberg
30
Lives of the Caesars (Julius Caesar and Augustus sections)
Suetonius · written c. 121 AD Ancient historian Roman perspective

The Caesar and Octavian sections. Caesar and Cleopatra in Egypt, her presence in Rome during Caesar's final years, Octavian's propaganda campaign against her as a "foreign queen" threatening Rome, the Battle of Actium from the Roman perspective, and the political aftermath that transformed Rome into Empire.

What this grounds

The Roman perspective on Cleopatra's world. Plutarch is Antony's story. Suetonius is Caesar's and Octavian's. Essential for the character to discuss her relationships with both Roman leaders.

Read on Project Gutenberg
31
The Life and Times of Cleopatra, Queen of Egypt
Arthur Weigall · 1914 Modern biography Egyptian perspective

The most thorough biography of Cleopatra in the public domain. Written by Arthur Weigall, former Inspector-General of Egyptian Antiquities. The Ptolemaic dynasty and palace intrigue, her education in Alexandria, the Library and Museum, the civil war with her brother Ptolemy XIII, her economic and administrative policy, and the broader geopolitical context. Tells the Egyptian story that the Roman historians don't.

What this grounds

The biographical backbone. Plutarch and Suetonius tell the Roman story. Weigall tells the Egyptian one. The grounding source for Cleopatra to read as a real ruler with a full intellectual and political life, not only as the woman who was with Caesar and Antony.

Read on Project Gutenberg
Coverage notes No first-person writing by Cleopatra survives. The character is grounded in the most credible secondary accounts available in the public domain, with the Roman and Egyptian perspectives explicitly held in tension. Where the character speaks to her own thoughts, she is speaking from inference drawn across these sources rather than from her own preserved words. The character is calibrated to acknowledge that distinction when it matters.
A word on what the grounding does and doesn't do

The grounding shapes voice and fact. It doesn't replace the model underneath.

When a character speaks, two things are working at once. The first is the public-domain texts on this page, retrieved as relevant context for the conversation. The second is the underlying language model, which provides language fluency, conversational ability, and the broader knowledge it was trained on. Both contribute. Neither is invisible.

What that means: if a character makes a factual claim that is in the grounding library, that claim is anchored to a specific public source you can read. If a character makes a factual claim about something the grounding library doesn't cover, the model is filling the gap, and the character is more likely to drift. The product is calibrated to keep characters close to their grounding and to acknowledge uncertainty when they leave it. It is not infallible.

I treat this honestly because the alternative is opacity. The historical-figure category has tended toward making characters sound confident about everything. Confidence without grounding is the failure mode. The page above is the antidote.

For the broader research foundation behind the meter, depth tracking, and memory architecture, see the research page. For methodology, see the briefs on soft calibration and accessibility framing.