The Ulugh Beg Madrassa has an imposing portal and was the seat of learning during Ulugh Beg’s ( Timur’s grandson) rule. It has a mosque, lecture rooms and dormitory. During the 15th century it was a seat of scientific learning. Ulugh Beg (1393-1449), the well renowned astronomer, scientist and benign ruler of his time himself taught here.
Inner court of Ulugh Beg Madrassa

You can see on this picture the Madrasa of Ulug Beg, the first one built on the Registan, around 1420.
Ulug Beg was the grandson of Tamerlane. His main interest lied in sciences. His skills for politics were not good and he was murdered by his own son two years after he became Khan.
As well as this madrasa, he built several others in the main cities of the Empire (for instance in Bukhara), to develop education.