Before accepting sannyāsa (the renounced order), Lord Caitanya was known as Viśvambhara. The word viśvambhara refers to one who maintains the entire universe and who leads all living entities. This maintainer and leader appeared as Lord Śrī Kṛṣṇa Caitanya to give humanity these sublime teachings.
(Sri Caitanya Caritamrta------preface).

Furthermore, Lord Caitanya is also the master of all wealth, strength, fame, beauty, knowledge and renunciation because He is Śrī Kṛṣṇa Himself. He is described as pūrṇa, or complete. In the feature of Lord Caitanya, the Lord is an ideal renouncer, just as Śrī Rāma was an ideal king. Lord Caitanya acceptedthe order of sannyāsa and exemplified exceedingly wonderful principles in His own life. No one can compare to Him in the order of sannyāsa. Although in Kali-yuga acceptance of thesannyāsa order is generally forbidden, Lord Caitanya accepted it because He is complete in renunciation. Others cannot imitate Him but can only follow in His footsteps as far as possible. Those who are unfit for this order of life are strictly forbidden by the injunctions of the śāstras to accept it. Lord Caitanya, however, is complete in renunciation as well as all other opulences. He is therefore the highest principle of the Absolute Truth.
(Sri Caitanya Caritamrta-------1:2:5------purport).

Śrī Caitanya Mahāprabhu accepted sannyāsa so that even a foolish person who accepted Him as an ordinary sannyāsī would offer Him respect, for this would help diminish his material distresses and ultimately liberate him from the material clutches. Śrīla Bhaktisiddhānta Sarasvatī points out in this connection that Śrī Kṛṣṇa Caitanya Mahāprabhu is the combined form of Śrī Rādhā and Kṛṣṇa (mahāprabhu śrī-caitanya, rādhā-kṛṣṇa—nahe anya). Therefore when fools considered Caitanya Mahāprabhu to be an ordinary human being and thus treated Him disrespectfully, the merciful Lord, in order to deliver these offenders, accepted sannyāsa so that they would offer Him obeisances, accepting Him as a sannyāsī. ŚrīCaitanya Mahāprabhu accepted sannyāsa to bestow His great mercy on people in general, who cannot appreciate Him as Rādhā and Kṛṣṇa Themselves.
(Sri Caitanya Caritamrta-------1:8:11------purport).

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.
(Sri Caitanya Caritamrta-------1:3:34------purport).

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.
(Sri Caitanya Caritamrta-------1:3:34------purport).

Śrī Caitanya Mahāprabhu knew very well that His acceptance of sannyāsa was a thunderbolt for His mother. He therefore called for His mother and the devotees from Māyāpura, and by the arrangement of Śrī Advaita Ācārya, He met them for the last time after His acceptance of sannyāsa. His mother was overwhelmed with grief when she saw that He was clean-shaven. There was no longer any beautiful hair on His head. Mother Śacī was pacified by all the devotees, and Lord Caitanya Mahāprabhu asked her to cook for Him because He was very hungry, not having taken anything for three days. His mother immediately agreed, and forgetting everything else, she cooked for Śrī Caitanya Mahāprabhu during all the days she was at the house of Śrī Advaita Prabhu. Then, after a few days, Śrī Caitanya Mahāprabhu requested His mother's permission to go to Jagannātha Purī. At His mother's request, He made Jagannātha Purī His headquarters after His acceptance of sannyāsa. Thus everything was adjusted, and with His mother's permission Śrī Caitanya Mahāprabhu proceeded toward Jagannātha Purī.
(Sri Caitanya Caritamrta-------2:1:95------purport).

There was no need for Lord Śrī Caitanya Mahāprabhu to accept sannyāsa, for He is God Himself and therefore has nothing to do with the material bodily concept of life. Śrī CaitanyaMahāprabhu did not identify Himself with any of the eight varṇas and āśramas, namely, brāhmaṇa, kṣatriya, vaiśya, śūdra, brahmacārī, gṛhastha, vānaprastha and sannyāsa. He identified Himself as the Supreme Spirit. Śrī Caitanya Mahāprabhu, or for that matter any pure devotee, never identifies with these social and spiritual divisions of life, for a devotee is always transcendental to these different gradations of society. Nevertheless, Lord Caitanya decided to accept sannyāsa on the grounds that when He became a sannyāsī everyone would show Him respect and in that way be favored. Although there was actually no need for Him to accept sannyāsa, He did so for the benefit of those who might think Him an ordinary human being. The main purpose of His accepting sannyāsa was to deliver the Māyāvādī sannyāsīs.
(Sri Caitanya Caritamrta-------1:7:33------purport).

In this verse it is clearly indicated that although Lord Caitanya Mahāprabhu converted Muslims and other mlecchas into devotees, the impersonalist followers of Śaṅkarācārya could not be converted. After accepting the renounced order of life, Caitanya Mahāprabhu converted many karma-niṣṭhas who were addicted to fruitive activities, many great logicians like Sārvabhauma Bhaṭṭācārya, nindakas (blasphemers) like Prakāśānanda Sarasvatī, pāṣaṇḍīs (nondevotees) like Jagāi and Mādhāi, and adhama paḍuyās (degraded students) like Mukunda and his friends. All of them gradually became devotees of the Lord, even the Pāṭhāns (Muslims), but the worst offenders, the impersonalists, were extremely difficult to convert, for they very tactfully escaped the devices of Lord Caitanya Mahāprabhu.
(Sri Caitanya Caritamrta-------1:7:39------purport).

Māyāvādī sannyāsīs are very puffed up if they hold the elevated sannyāsa title Tīrtha, Āśrama or Sarasvatī. Even among Māyāvādīs, those who belong to other sampradāyas and hold other titles, such as Vana, Araṇya or Bhāratī, are considered to be lower-grade sannyāsīs. Śrī Caitanya Mahāprabhu accepted sannyāsa from the Bhāratī-sampradāya, and thus He considered Himself a lower sannyāsī than Prakāśānanda Sarasvatī. To remain distinct from Vaiṣṇava sannyāsīs, the sannyāsīs of the Māyāvādi-sampradāya always think themselves to be situated in a very much elevated spiritual order, but Lord Śrī Caitanya Mahāprabhu, in order to teach them how to become humble and meek, accepted Himself as belonging to a lower sampradāya of sannyāsīs. Thus He wanted to point out clearly that a sannyāsī is one who is advanced in spiritual knowledge. One who is advanced in spiritual knowledge should be accepted as occupying a better position than those who lack such knowledge.
(Sri Caitanya Caritamrta-------1:7:64------purport).