CC Ādi 17.8
īśvara-purīra saṅge tathāi milana
Thereafter the Lord went to Gayā. There He met Śrīla Īśvara Purī.
Śrī Caitanya Mahāprabhu went to Gayā to offer respectful oblations to His forefathers. This process is called piṇḍa-dāna. In Vedic society, after the death of a relative, especially one’s father or mother, one must go to Gayā and there offer oblations to the lotus feet of Lord Viṣṇu. Therefore hundreds and thousands of men gather in Gayā daily to offer such oblations, or śrāddha. Following this principle, Lord Caitanya Mahāprabhu also went there to offer piṇḍa to His dead father. Fortunately He met Īśvara Purī there.