In the traditional reckoning a son owes his departed father the shraddha ceremony, and the most meritorious place in all India to perform it is Gaya, where the offering is made at the temple of Vishnupada — the imprint of Vishnu's foot. Some years after Jagannatha Mishra's death, Nimai set out from Nabadwip for Gaya to discharge that duty, taking with Him a party of His own students. He went as what He then was: a young married pandit, the most celebrated logician in Nadia, travelling to perform a family obligation. He returned as someone His own town could scarcely recognise.
At Gaya He performed the ceremony for His father. And at the Vishnupada temple He met a wandering Vaishnava sannyasi named Ishvara Puri — a disciple of Madhavendra Puri, and thus an inheritor of a line in which the mood of intense, personal, emotionally saturated devotion to Krishna had been carefully preserved. Madhavendra Puri is the figure in whom Gaudiya Vaishnavas locate the first full flowering of that mood, and Ishvara Puri had absorbed it from him directly. From Ishvara Puri, Nimai received initiation and the ten-syllable Krishna mantra.
The biographies are unanimous that the change was immediate and complete. The young man who had walked to Gaya arguing points of grammar with His students walked back from it weeping, trembling, losing consciousness, unable to hold a conversation without breaking into the names of Krishna. On the road home He is described as scarcely able to travel, overcome again and again, His students bewildered and increasingly alarmed by what had happened to their teacher. The disputatious brilliance was simply gone. What replaced it was an absorption so total that the ordinary business of life could no longer get His attention.
Nabadwip's reaction was, understandably, confusion. The town's leading pandits had spent years being defeated by this man in argument; they now found Him unwilling to argue at all. When His students assembled for their grammar lessons, He is said to have told them that every rule of grammar reminded Him of Krishna, and to have wept instead of teaching, until at length He closed His school altogether. Those who had resented His pride concluded He had gone mad, or that grief had unbalanced Him. Only a small number of people in Nabadwip — Advaita Acharya at Shantipura, who had been praying for exactly this; Srivasa Pandit, in whose courtyard the movement would shortly begin; and a handful of others already inclined to devotion — understood what they were looking at.
Gaudiya theology treats this episode with some care, because on its face it presents a difficulty. If Chaitanya Mahaprabhu is Krishna Himself, He cannot have needed initiation from anyone, and cannot have acquired at Gaya a devotion He did not previously possess. The tradition's answer is that the Lord accepted a spiritual master in order to establish the principle for everyone else: that no one, however exalted, approaches Krishna without taking shelter of a guru in an authentic disciplic line, and that the Lord submitted to this rule Himself so that no one afterwards could claim exemption from it. On the same reading, the ecstasy that manifested on the road home was not newly created but newly displayed — the interior life He had come to demonstrate, now allowed to show.
Whatever construction is placed on it, the practical consequence is not in dispute. Everything that Sri Chaitanya Mahaprabhu is remembered for begins on the far side of this journey. Before Gaya He is a provincial scholar of exceptional gifts, and the historical record would have kept His name, if at all, as a footnote in the history of Navya-nyaya logic. After Gaya He is the founder of a movement. Within a very short time of His return the nightly gatherings at Srivasa Pandit's house had begun, and from them the sankirtana movement went out into the streets of Nabadwip and, in the centuries following, considerably further.
It is worth noticing that the change was not from irreligion to religion. Nimai Pandita had been a perfectly orthodox brahmana, performing the prescribed duties, observing Ekadashi, travelling to Gaya to make an offering for His father. What changed at Gaya was not His observance but the object of His attention — and the tradition holds this up as the exact distinction it wants understood. Religion correctly performed is not the goal; it is the ground from which love of God may or may not grow. At Gaya, in the case of this particular pilgrim, it grew.