Babylon fell to Cyrus of Persia in 538 BC, but the city was spared. The great empire was finished. The use of cuneiform script formed a strong bond. Laws, tax accounts, stories, school lessons, personal letters were impressed on soft clay tablets and then were baked in the hot sun or in ovens. From one region, the site of ancient Nippur, there have been recovered some 50,000 tablets.
Many university libraries have large collections.
Deciphering cuneiform succeeded the Egyptian hieroglyphic. Indeed, just as for hieroglyphics, the key to deciphering was a trilingual inscription. However, all three were unknown. Only because Old Persian has only 43 signs and had been the subject of serious investigation since the beginning of the 19th century was the deciphering accomplished. Nonetheless, progress was very slow.