One Thousand and One Conjectures

The Polya urn — the classic mathematical model of path dependence, in which each ball drawn adds another of its color so that early luck compounds forever — is here applied to the medieval pilgrimage market. Pilgrims bought cheap metal badges at…

Great Zimbabwe on its inland plateau and the Swahili port of Kilwa on the Indian Ocean coast are the two famous sites joined here, and the joint is metrological. Kilwa struck its own coins to a known weight standard and shipped the…

Caravanserais — the fortified roadside inns of the Silk Road and the Islamic world — existed to break overland journeys into daily stages, so their spacing was governed by a physical constant: how far a loaded camel walks in a day. The…

The Cistercian order expanded by filiation — mother abbeys founding daughter houses — under statutes and economic pressures that discouraged crowding, since each abbey lived off its own granges and lands. That is the setup of competitive exclusion in ecology, where territorial…

The Byzantine empire ran a fire-signal chain that could relay news of Arab raids from the Cilician frontier to Constantinople within hours — a communication channel in the exact information-theoretic sense, and one operating under noise, since fog and haze could blind…

As chess spread from India across Eurasia, both its objects and its rules mutated regionally: the piece carved as an elephant in the Islamic world became the bishop in Europe, and the moves themselves varied between documented regional rule sets. Linguistics maps…

Gothic churches were built in successive campaigns over decades, and masons could watch how earlier bays and earlier buildings cracked, leaned, or stood. Modern limit analysis can compute, for any buttress geometry, how far it sits from the thrust-line optimum — the…

This joins Gothic cathedral construction to the economics of competitive escalation — the same arms-race dynamics seen in armament races and advertising wars. A cathedral's height was a prestige signal aimed at specific rivals, and the relevant rivals were local: the sees…

This joins Viking shipbuilding to modern fracture mechanics. A clinker hull is a shell of overlapping oak planks, and its worst enemy is a running split: a crack that starts at a fastening and propagates along the grain. Fracture mechanics says such…

This joins medieval church archaeology to geomagnetism. Churches were meant to face east, yet surveyed orientations scatter by several degrees, and the scatter is usually written off as sloppy surveying. But once the magnetic compass entered the building trades — plausibly around…

This joins the mysterious accuracy of medieval portolan charts to the statistics of error averaging. Portolans appear in the late 13th century already startlingly accurate, with no known surveying campaign behind them; the conjecture's explanation is that they are averaged compass logs…

This joins the Classic Maya collapse to the physics of percolation — the mathematics of systems that fail not gradually but when a critical threshold is crossed. Lowland Maya cities rode out the dry season on constructed reservoirs, so each city's resilience…

This joins the vast water network of medieval Angkor to the theory of self-organized criticality — the sandpile physics in which a slowly loaded system tunes itself to a critical state where avalanches of every size occur, their sizes following a power…

Markowitz's portfolio theory says diversification pays exactly when the assets you spread across are weakly correlated — variance falls fastest where covariance is low. The medieval open-field system's scattered strips, a puzzle ever since they were read as peasant insurance, are a…

Airborne LiDAR has stripped the canopy from the Maya lowlands and revealed settlement in the tens of thousands of structures, making true regional settlement hierarchies measurable for the first time; settlement-scaling theory, meanwhile, holds that integrated urban systems produce Zipfian rank-size distributions…

RT60 — the time a sound takes to decay by sixty decibels — is the basic figure of architectural acoustics, and a great stone nave can hold a note for many seconds; a fast syllabic melody blurs into mud in such a…

The Norse thing — the open-air assembly at which law was recited, cases were pled and decisions proclaimed — was above all an exercise in unamplified speech before a crowd, and sites like Thingvellir have long invited the suspicion that their cliffs…

Muqarnas — the honeycomb vaulting of Islamic architecture, thousands of small stepped niches filling domes and squinches — is usually read as pure geometry made ornament. But a surface of many differently sized and angled cells is exactly what a modern acoustician…

Medieval masons cut personal marks into the blocks they dressed — piece-work signatures for the paymaster — and a cathedral wall therefore carries, frozen in stone, a record of who cut what. Work organisation leaves statistical fingerprints: if masons produced blocks in…

Joins experience-curve economics to Islamic mathematical geography. In manufacturing, quality improves as a power law of cumulative output — the experience curve — because every unit produced teaches its producers. Every mosque is such a unit: it must face Mecca, its measurable…

Romanesque corbel tables read as carnivalesque miscellany, but carving proceeded bay by bay from scaffolds, one carver working consecutive blocks with whatever type he was fluent in that week. Subject types should therefore show strong serial autocorrelation around the eaves — runs…