Lord Caitanya remained a householder only until His twenty-fourth year had passed. Then He entered the renounced order and remained manifest in this material world until His forty-eighth year. Therefore His śeṣa-līlā, or the final portion of His activities, lasted twenty-four years.
Some so-called Vaiṣṇavas say that the renounced order of life was not accepted in the Vaiṣṇava sampradāya, or disciplic succession, until Lord Caitanya. This is not a very intelligent proposition. Śrī Caitanya Mahāprabhu took the sannyāsa order from Śrīpāda Keśava Bhāratī, who belonged to the Śaṅkara sect, which approves of only ten names for sannyāsīs. Long before the advent of Śrīpāda Śaṅkarācārya, however, the sannyāsa order existed in the Vaiṣṇava line of Viṣṇu Svāmī. In the Viṣṇu Svāmī Vaiṣṇava sampradāya, there are ten different kinds of sannyāsa names and 108 different names for sannyāsīs who accept the tri-daṇḍa, the triple staff of sannyāsa. This is approved by the Vedic rules. Therefore Vaiṣṇava sannyāsa was existent even before the appearance of Śaṅkarācārya, although those who know nothing about Vaiṣṇava sannyāsa unnecessarily declare that there is no sannyāsa in the Vaiṣṇava sampradāya.
During the time of Lord Caitanya, the influence of Śaṅkarācārya in society was very strong. People thought that one could accept sannyāsa only in the disciplic succession of Śaṅkarācārya. Lord Caitanya could have performed His missionary activities as a householder, but He found householder life an obstruction to His mission. Therefore He decided to accept the renounced order, sannyāsa. Since His acceptance of sannyāsa was also designed to attract public attention, Lord Caitanya, not wishing to disturb the social convention, took the renounced order of life from a sannyāsī in the disciplic succession of Śaṅkarācārya, although sannyāsa was also sanctioned in the Vaiṣṇava sampradāya.
In the Śaṅkara-sampradāya there are ten different names awarded to sannyāsīs: (1) Tīrtha, (2) Āśrama, (3) Vana, (4) Araṇya, (5) Giri, (6) Parvata, (7) Sāgara, (8) Sarasvatī, (9) Bhāratī and (10) Purī. Before one enters sannyāsa, he has one of the various names for a brahmacārī, the assistant to a sannyāsī. Sannyāsīs with the titles Tīrtha and Āśrama generally stay at Dvārakā, and their brahmacārī name is Svarūpa. Those known by the names Vana and Araṇya stay at Puruṣottama, or Jagannātha Purī, and their brahmacārī name is Prakāśa. Those with the names Giri, Parvata and Sāgara generally stay at Badarikāśrama, and their brahmacārī name is Ānanda. Those with the titles Sarasvatī, Bhāratī and Purī usually live at Śṛṅgerī in South India, and their brahmacārī name is Caitanya.
Śrīpāda Śaṅkarācārya established four monasteries in India, in the four directions (north, south, east and west), and he entrusted them to four sannyāsīs who were his disciples. Now there are hundreds of branch monasteries under these four principal monasteries, and although there is an official symmetry among them, there are many differences in their dealings. The four different sects of these monasteries are known as Ānandavāra, Bhogavāra, Kīṭavāra and Bhūmivāra, and in course of time they have developed different ideas and different slogans.
According to the regulation of the disciplic succession, one who wishes to enter the renounced order in Śaṅkara’s sect must first be trained as a brahmacārī under a bona fide sannyāsī, The brahmacārī’s name is ascertained according to the group to which the sannyāsī belongs. Lord Caitanya accepted sannyāsa from Keśava Bhāratī. When He first approached Keśava Bhāratī, He was accepted as a brahmacārī with the name Śrī Kṛṣṇa Caitanya Brahmacārī. After He took sannyāsa, He preferred to keep the name Kṛṣṇa Caitanya.
The great authorities in the disciplic succession had not offered to explain why Lord Caitanya refused to take the name Bhāratī after He took sannyāsa from a Bhāratī, until Śrīla Bhaktisiddhānta Sarasvatī Gosvāmī Mahārāja volunteered the explanation that because a sannyāsī in the Śaṅkara-sampradāya thinks that he has become the Supreme, Lord Caitanya, wanting to avoid such a misconception, kept the name Śrī Kṛṣṇa Caitanya, placing Himself as an eternal servitor. A brahmacārī is supposed to serve the spiritual master; therefore He did not negate that relationship of servitude to His spiritual master. Accepting such a position is favorable for the relationship between the disciple and the spiritual master.
The authentic biographies also mention that Lord Caitanya accepted the daṇḍa (rod) and begging pot, symbolic of the sannyāsa order, at the time He took sannyāsa.