Although the archaeological site at Harappa was partially damaged in 1857 when engineers constructing the Lahore-Multan railroad used brick from the Harappa ruins for track ballast, an abundance of artefacts have nevertheless been found. Punjab was part of the great ancient empires including the Gandhara Mahajanapadas, Achaemenids, Macedonians, Mauryas, Kushans, Guptas, and Hindu Shahi. It also comprised the Gujar empire for a period of time, otherwise known as the Gurjara-Pratihara empire Agriculture flourished and trading cities (such as Multan and Lahore) grew in wealth.