Iran's earliest script survives on about 1,600–1,700 accounting tablets; its numbers are read, but whether its other signs write words, and how it relates to Linear Elamite, is disputed.

Whether the short Harappan inscriptions record speech at all has been argued with entropy statistics for two decades; no test yet separates writing from emblem systems decisively.

The city from which Sargon and his successors ruled Mesopotamia c. 2300 BCE has never been securely located, despite more than a century of searching in central Iraq.

Competing High, Middle, Low and Ultra-Low chronologies place Hammurabi and the fall of Babylon up to about 150 years apart; no single model integrates all the evidence.

Minoan Linear A can be roughly sounded out through Linear B values, but no proposed language family has been shown to fit better than random controls.

Meroitic script has been readable since Griffith's work of 1909–1911, but outside formulaic texts the language of the Kingdom of Kush is still largely untranslated.

Ptolemy's catalogue of about 1,025 stars claims his own observations; statistical anomalies suggest much of it derives from Hipparchus three centuries earlier.

Roman census totals jump from about 910,000 in 70/69 BCE to 4,063,000 in 28 BCE; whether this reflects a change in who was counted or real growth remains disputed.

Ancient DNA confirms Yersinia pestis caused the First Pandemic (541–c.750), but estimates of its mortality and long-term consequences range from catastrophic to modest.

Islamic tradition credits the caliph ʿUthmān (c. 650); some scholars place closure under ʿAbd al-Malik and al-Ḥajjāj (c. 700) or later. Manuscript evidence is now testing these positions.

Proposed dates for the poem range from about 700 to the early eleventh century, the date of its only manuscript, and rest on metre, language, palaeography and historical context.

Robert Hartwell's estimate of about 125,000 tons of iron in 1078 is widely repeated, but it rests on fiscal records whose relation to total output is disputed.

Gunpowder formulas appear in China by 1044 and in Arabic and Latin texts by the later 1200s, but the path between them is unattested.

Several of the largest volcanic sulfate deposits of the last millennium, in 1230, 1286, 1458, 1695 and 1809, have no securely identified source volcano.

Copernicus used devices found earlier in al-Ṭūsī and Ibn al-Shāṭir, but no document shows how a text containing them reached him or his teachers.

Plague devastated Egypt and North Africa in 1347–49, but whether it crossed the Sahara or reached the Horn and East Africa is unresolved.

Madhava's school derived power series for π, sine and cosine before 1500; whether Jesuits in Kerala carried them to Europe remains undocumented.

Geology and archaeology show two great tsunamis struck northern Sumatra around 1394 and 1450, but no contemporary text describing either has been identified.

Andean knotted cords encode numbers in a known decimal system; whether colour, ply, attachment and knot direction also record names, categories or narrative remains open.

Glyph-level variation in the earliest Mainz types has been read both as evidence against the punch, matrix and hand mould, and as fully compatible with it.

Estimates of the share of fifteenth- and sixteenth-century editions that survive in no copy vary widely, and depend on statistical models that have rarely been tested against later discoveries.

Estimates of the hemisphere's population on the eve of contact run from about 8 million to over 100 million, and the scale of the collapse depends on which is right.

Andrés Reséndez's estimate of 2.5 to 5 million enslaved Indigenous people is the only hemispheric figure, and it rests on regional extrapolation rather than a count.

European slave trading in the Indian Ocean has been tentatively counted, but the combined volume of Dutch, Portuguese, French, British, Arab, Swahili and South Asian trades remains unknown.

Tax surveys show rapid growth in Anatolia to about 1580, but whether the decline that followed was a demographic collapse or an artefact of changing registration remains unsettled.

Estimates of the share of Spanish American silver that ended up in China vary widely because mint, shipping and Chinese monetary records have never been reconciled in one account.

Late Ming population estimates run from about 150 million to over 200 million, so the scale of the mid-seventeenth-century collapse remains uncertain by tens of millions.

Contemporary claims of 154,000 to 300,000 Protestant victims are rejected, but the modern figure of roughly 4,000 killed has never been built from a full victim-level count.

Rawski's 1979 estimate of 30–45 percent male literacy in Qing China has never been tested against a systematic count of signatures and marks on contracts.

Optical effects, perspective geometry and technical imaging have been read for and against Vermeer's use of a camera obscura, with no documentary evidence either way.

Fisher showed in 1936 that Mendel's ratios fit theory improbably well; a century of explanations has not produced documentary evidence of how the counts were made.

India probably lost more lives than any other country in the 1918–19 pandemic, but estimates run from about 12 to over 17 million and the causes remain debated.

Estimates of excess deaths in China's Great Leap famine range from under 20 million to 45 million, depending on sources, baselines and assumptions about registration.