One of the most accomplished astronomers of the Middle Ages was born on today’s date in 1394 — 625 years ago. He built a university and an observatory and compiled a major star catalog. But he was also a political leader, and that brought about an early and unfortunate end to his career.

Ulugh Beg was the grandson of Tamerlane, a famous ruler who built an empire in the Middle East. When Tamerlane died, Ulugh Beg’s father took over the empire. And he installed Ulugh Beg, who was just 16 years old, as the governor of Samarkand, a major city in present-day Iran.

Over the decades, Ulugh Beg built a major university there, which he staffed with mathematicians and astronomers. And he did his own astronomical research.

To further that work, in 1428 he built an observatory at Samarkand. It included a device for accurately measuring the positions of stars. He used those positions to compile a catalog of more than a thousand stars. It corrected some errors made in the most-used catalog of the time, which had been compiled more than a thousand years earlier. He also calculated the length of the year, and the angle of Earth’s tilt on its axis.

After his father died, in 1447, Ulugh Beg faced challenges from many quarters, including his own son. He eventually surrendered to his son, which was a bad idea. The son had Ulugh Beg killed — ending the life and work of one of the ancient world’s great astronomers.

Script by Damond Benningfield