Lane 01
Wars & Conflicts
Battles, sieges, campaigns, and treaties from the Assyrian conquests to the post-1945 conflicts — mapped by start date, with duration bars for protracted engagements.
A Reference Work for World History
The Comparative Timeline
78,400+ encyclopedia entries and 60,200+ indexed primary-source documents, aligned on a single axis from 2000 BCE to the present.
Four Default Overlay Lanes
Stack civilizations, movements, and events on a single horizontal axis.
Each lane carries independently filterable markers drawn from peer-reviewed and primary sources. Toggle lanes on or off to isolate a single thread, or overlay all four to build a comparative argument.
Lane 02
Science & Technology
Discoveries, inventions, and foundational publications — from Euclid's Elements to the sequencing of the human genome — dated to their first attested appearance.
Lane 03
Art & Cultural Movements
Movements, monuments, and canonical works — from the Amarna period through Tang poetry, Renaissance frescoes, and twentieth-century avant-gardes.
Lane 04
Politics & Governance
Foundations, reforms, constitutions, treaties, and major legislative acts — from the Code of Hammurabi through the postwar international order.
Preview
1450 – 1700, four lanes overlaid
A 250-year span showing the fall of Constantinople, the printing press in Mainz, the Ming maritime voyages, and the Peace of Westphalia — all on a single axis.
Methodology
How every marker on the timeline is sourced, dated, and rated.
The timeline is a research instrument, not a graphic. Every marker is governed by the same editorial rules that govern the encyclopedia entries beneath it.
Every event recorded on the Comparative Timeline carries at least three independent citations drawn from peer-reviewed scholarship, contemporary primary sources, or both. Where conventional dating is contested — as with the Roman calendar reform of 46 BCE or the chronology of the New Kingdom — the marker is plotted at the most widely accepted scholarly position, and the dispute is documented in a footnote anchored to the entry itself.
Confidence ratings are assigned on a four-tier scale: Established (corroborated by three or more independent primary or peer-reviewed sources), Standard (supported by mainstream scholarship with minor dating variation), Disputed (active scholarly disagreement, marker carries a footnote), and Provisional (single high-quality source, awaiting corroboration). The rating appears as a small mark beside each marker and is never concealed.
Date ranges follow the same conventions as the underlying encyclopedia: BCE/CE throughout, with the proleptic Julian calendar applied pre-1582 only where it is the convention of the cited scholarship. Apparent time-machine effects between civilizations — the simultaneous 19th century of Qing China and Meiji Japan, for instance — are preserved as they appear in the literature, and the user can toggle a "synchronoptic" view that surfaces these alignments explicitly.
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i.
Three-source rule. No marker is plotted without at least three independent citations, except in the Provisional tier where a single high-quality source is annotated as such.
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ii.
Editorial board review. Markers touching the period 500 BCE – 1900 CE are reviewed by at least one of the 41 credentialed historians, archaeologists, or classicists on staff before publication.
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iii.
Disputed claims are labeled. Mainstream scholarship is the default; contested chronologies are flagged inline and the dissenting sources are linked.
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iv.
No anonymous edits. Every marker carries a byline to the editor who placed it, with a link to their full editorial record.
In Practice
Three researcher outcomes the timeline is built for.
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01
Building a comparative essay
A student writing on the simultaneous development of early modern state finance in England, the Dutch Republic, and the Tokugawa shogunate overlays the Politics lane with a custom finance-events filter and exports the resulting frame as a Chicago-formatted citation set.
- Layer a custom user filter on top of any of the four default lanes
- Pin a 50-to-250-year window and share the URL with collaborators
- Export the visible markers as Chicago, MLA, or APA citations in one action
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02
Cross-referencing for an exam
A teacher preparing an AP World History unit on transoceanic contact (1400 – 1700) opens the four default lanes, restricts the axis to that window, and uses the resulting overlay to verify that the unit's chronology covers the canonical primary-source readings.
- Restrict the axis to any user-defined window
- Toggle the primary-source layer to surface original documents next to dated events
- Print or PDF the resulting frame for distribution to students
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03
Verifying a contested claim
A reader encounters the claim that the printing press reached Sub-Saharan Africa before 1700, opens the Science lane with an Africa regional filter, and inspects the Disputed markers — each one links directly to the underlying primary sources and the editorial footnote.
- Filter any lane by region, polity, or 312-entry civilization index
- Inspect the confidence rating and source chain behind any single marker
- Open the linked encyclopedia entry for full citation context
I use the comparative timeline as a unit-planning instrument before I use it as a teaching instrument. The fact that a student can isolate a window, see four independent streams on a single axis, and then export a citation set they can defend in an exam is the part I have not seen any other reference do well.
Section Break
Open the Timeline.
Four lanes. One axis. Four thousand years of recorded history — verifiable marker by marker.
Free tier includes access to the timeline and 18,000+ encyclopedia entries. Pro adds 60,000+ primary-source documents and citation exports.