The Vedic Civilization spread along the length of the Sarasvati River to cover most of Northern India including Punjab. This civilization shaped subsequent cultures in the Indian subcontinent. The Punjab region was conquered by many ancient empires including the Gandhara, Nandas, Mauryas, Sungas, Kushans, Guptas, Palas, Gurjara-Pratiharas and Hindu Shahis. The furthest eastern extent of Alexander the Great's exploration was along the Indus River. Agriculture flourished and trading cities such as Jalandhar, Sangrur and Ludhiana grew in wealth.