Ulugh Beg's Observatory

1420 CE — Central Asia, Timurid Samarkand

Today: Samarkand, Uzbekistan

Timur's grandson governed Samarkand and cared more about astronomy than governing. He built a three-storey observatory around a marble arc 130 feet across, sunk into a trench in the hillside, and with it his astronomers measured the length of the year to within about 25 seconds of the modern figure — by naked eye, two centuries before the telescope. Their star catalogue was the most accurate since Ptolemy. Ulugh Beg was murdered on his son's orders in 1449, and religious conservatives razed the observatory; its foundations were only rediscovered in 1908.

Worth knowing: His astronomers timed the year to within roughly 25 seconds without a telescope. His reward was assassination by his own son, and the destruction of the instrument — the trench survived because it was underground, and was found by an archaeologist following a rumour.

Pattern: Information-medium revolution — A new way to record or transmit information lowers the cost of copying ideas and reorders who holds knowledge and power.

Entry 146 of 240 in Precedent, a walk through the whole human story in order.