Nor was Greek occupation the only source of the civilization of Sogdiana. Centuries rolled on, and at length the Saracens renewed, on their own peculiar basis, the mental cultivation which Sogdiana had received from Alexander. The cities of Bokhara and Samarcand have been famous for science and literature. Bokhara was long celebrated as the most eminent seat of Mahometan learning in central Asia; its colleges were, and are, numerous, accommodating from 60 to 600 students each. One of them gained the notice and the pecuniary aid of the Russian Empress Catharine.[32] Samarcand rivals Bokhara in fame; its university even in the last century was frequented by Mahometan youth from foreign countries. There were more than 300 colleges for students, and there was an observatory, celebrated in the middle ages, the ruins of which remain. Here lies the body of Timour, under a lofty dome, the sides of which are enriched with agate. "Since the time of the Holy Prophet," that is, Mahomet, says the Emperor Baber, "no country has produced so many Imaums and eminent divines as Mawar-al-nahar," that is, Sogdiana. It was celebrated for its populousness. At one time it boasted of being able to send out 300,000 foot, and as many horse, without missing them. Bridges and caravansaries abounded; the latter, in the single province attached to its capital, amounted to 2,000. In Bactriana, the very ruins of Balkh extend for a circuit of 20 miles, and Sir A. Burns wound through three miles of them continuously.