At the end of His twenty-fourth year, at the end of the fortnight of the waxing moon, Śrī Caitanya Mahāprabhu left Navadvīpa and crossed the river Ganges at a place known as Nidayāra-ghāṭa. Then He reached Kaṇṭaka-nagara, or Kāṭoyā (Katwa), where He accepted ekadaṇḍa-sannyāsa according to the Śaṅkarite system. Since Keśava Bhāratī belonged to the Śaṅkarite sect, he could not initiate Caitanya Mahāprabhu into the Vaiṣṇava sannyāsa order, whose members carry the tridaṇḍa.

Candraśekhara Ācārya assisted in the routine ceremonial work of the Lord's acceptance of sannyāsa. By the order of Śrī Caitanya Mahāprabhu, kīrtana was performed for the entire day, and at the end of the day the Lord shaved off His hair. On the next day He became a regular sannyāsī, with one rod (ekadaṇḍa). From that day on, His name was Śrī Kṛṣṇa Caitanya. Before that, He was known as Nimāi Paṇḍita. Śrī Caitanya Mahāprabhu, in the sannyāsa order, traveled all over Rāḍhadeśa, the region where the Ganges River cannot be seen. Keśava Bhāratī accompanied Him for some distance.
(Sri Caitanya Caritamrta--------1:17:272---------purport).

It is the desire of Lord Caitanya Mahāprabhu that the benevolent activities of the saṅkīrtana movement, which was inaugurated five hundred years ago in Navadvīpa, be spread all over the world for the benefit of all human beings. Unfortunately, there are many so-called followers of Caitanya Mahāprabhu who are satisfied simply to construct a temple, make a show of the Deities, collect some funds and utilize them for eating and sleeping. There is no question of their preaching the cult of Śrī Caitanya Mahāprabhu all over the world. But even though they are unable to do so, if anyone else does it they become envious. This is the condition of the modern followers of Caitanya Mahāprabhu. The Age of Kali is so strong that it affects even the so-called followers of Lord Caitanya. At least the followers of Caitanya Mahāprabhu must come out of India to preach His cult all over the world, for this is the mission of Lord Caitanya. The followers of Lord Caitanya must execute His will with heart and soul, being more tolerant than the trees and humbler than the straw in the street.
(Sri Caitanya Caritamrta--------1:9:47---------purport).

Śrīla Narottama dāsa Ṭhākura has sung:

śrī gauḍa-maṇḍala-bhūmi, yeba jāne cintāmaṇi,
tāra haya vrajabhūmi vāsa
"One who understands the transcendental nature of Navadvīpa and its surrounding area, where Śrī Caitanya Mahāprabhu enacted His pastimes, resides always in Vṛndāvana." Similarly,living in Jagannātha Purī is as good as living in Vṛndāvana. The conclusion is that Navadvīpa-dhāma, Jagannātha Purī-dhāma and Vṛndāvana-dhāma are identical.

However, if one goes to Mathurā-maṇḍala-bhūmi for sense gratification or to make a livelihood, he commits an offense and is condemned. Whoever does so must be penalized in the next life by becoming a hog or a monkey in Vṛndāvana-dhāma. After taking on such a body, the offender is liberated in the next life. Śrīla Bhaktisiddhānta Sarasvatī Ṭhākura remarks that residing in Vṛndāvana with a view to enjoy sense gratification surely leads a so-called devotee to a lower species.
(Sri Caitanya Caritamrta--------2:22:132---------purport).

Lord Śrī Caitanya Mahāprabhu did not manifest His spiritual potencies at Navadvīpa, but He did manifest them in South India and liberated all the people there.
At that time there were many smārtas (nondevotee followers of Vedic rituals) at the holy place of Navadvīpa, which was also the birthplace of Lord Śrī Caitanya Mahāprabhu. Followers of the smṛti-śāstra are called smārtas. Most of them are nondevotees, and their main business is following the brahminical principles strictly. However, they are not enlightened in devotional service. In Navadvīpa all the learned scholars are followers of the smṛti-śāstra, and Lord Caitanya Mahāprabhu did not attempt to convert them. Therefore the author has remarked that the spiritual potency Lord Śrī Caitanya Mahāprabhu did not manifest at Navadvīpa was by His grace manifested in South India. Thus everyone there became a Vaiṣṇava. By this it is to be understood that people are really interested in preaching in a favorable situation. If the candidates for conversion are too disturbing, a preacher may not attempt to spread Kṛṣṇa consciousness amongst them. It is better to go where the situation is more favorable. This Kṛṣṇa consciousness movement was first attempted in India, but the people of India, being absorbed in political thoughts, did not take to it. They were entranced by the political leaders. We preferred, therefore, to come to the West, following the order of our spiritual master, and by the grace of Lord Caitanya Mahāprabhu this movement is becoming successful.
(Sri Caitanya Caritamrta--------2:7:109---------translation and purport).

The saṅkīrtana movement went on from one part of the town to another, as the Lord wandered everywhere performing kīrtana. In this way He inundated the whole world by distributing love of Godhead.
One may raise the question how all three worlds became inundated with love of Kṛṣṇa, since Caitanya Mahāprabhu performed kīrtana only in the Navadvīpa area. The answer is that Lord Śrī Caitanya Mahāprabhu is Kṛṣṇa Himself. The entire cosmic manifestation results from the Lord's first setting it in motion. Similarly, since the saṅkīrtana movement was first set in motion five hundred years ago by Śrī Caitanya Mahāprabhu's desire that it spread all over the universe, the Kṛṣṇa consciousness movement, in continuity of that same motion, is now spreading all over the world, and in this way it will gradually spread all over the universe. With the spread of the Kṛṣṇa consciousness movement, everyone will merge in an ocean of love of Kṛṣṇa.
(Sri Caitanya Caritamrta--------1:13:32---------translation and purport).

The Lord had a very high estimation of the affections of the damsels of Vrajabhūmi (Vṛndāvana) for Kṛṣṇa, and in appreciation of their unalloyed service to the Lord, once Śrī Caitanya Mahāprabhu chanted the holy names of the gopīs (cowherd girls) instead of the names of the Lord. At this time some of His students, who were also disciples, came to see Him, and when they saw that the Lord was chanting the names of the gopīs, they were astonished. Out of sheer foolishness they asked the Lord why He was chanting the names of the gopīs and advised Him to chant the name of Kṛṣṇa. The Lord, who was in ecstasy, was thus disturbed by these foolish students. He chastised them and chased them away. The students were almost the same age as the Lord, and thus they wrongly thought of the Lord as one of their peers. They held a meeting and resolved that they would attack the Lord if He dared to punish them again in such a manner. This incident provoked some malicious talks about the Lord on the part of the general public.
When the Lord became aware of this, He began to consider the various types of men found in society. He noted that especially the students, professors, fruitive workers, yogīs, nondevotees, and different types of atheists were all opposed to the devotional service of the Lord. "My mission is to deliver all the fallen souls of this age," He thought, "but if they commit offenses against Me, thinking Me to be an ordinary man, they will not benefit. If they are to begin their life of spiritual realization, they must some way or another offer obeisances unto Me." Thus the Lord decided to accept the renounced order of life (sannyāsa) because people in general were inclined to offer respects to a sannyāsī.

Five hundred years ago the condition of society was not as degraded as it is today. At that time people would show respects to a sannyāsī, and the sannyāsī was rigid in following the rules and regulations of the renounced order of life. Śrī Caitanya Mahāprabhu was not very much in favor of the renounced order of life in this age of Kali, but that was only for the reason that very few sannyāsīs in this age are able to observe the rules and regulations of sannyāsa life. Śrī Caitanya Mahāprabhu decided to accept the order and become an ideal sannyāsī so that the general populace would show Him respect. One is duty-bound to show respect to a sannyāsī, for a sannyāsī is considered to be the master of all varṇas and āśramas.

While He was contemplating accepting the sannyāsa order, it so happened that Keśava Bhāratī, a sannyāsī of the Māyāvādī school and resident of Katwa (in Bengal), visited Navadvīpa and was invited to dine with the Lord. When Keśava Bhāratī came to His house, the Lord asked him to award Him the sannyāsa order of life. This was a matter of formality. The sannyāsa order is to be accepted from another sannyāsī. Although the Lord was independent in all respects, still, to keep up the formalities of the śāstras, He accepted the sannyāsa order from Keśava Bhāratī, although Keśava Bhāratī was not in the Vaiṣṇava-sampradāya (school).

After consulting with Keśava Bhāratī, the Lord left Navadvīpa for Katwa to formally accept the sannyāsa order of life. He was accompanied by Śrīla Nityānanda Prabhu, Candraśekhara Ācārya, and Mukunda Datta. Those three assisted Him in the details of the ceremony. The incident of the Lord's accepting the sannyāsa order is very elaborately described in the Caitanya-bhāgavata by Śrīla Vṛndāvana dāsa Ṭhākura.

Thus at the end of His twenty-fourth year the Lord accepted the sannyāsa order of life in the month of Māgha. After accepting this order He became a full-fledged preacher of the Bhāgavata-dharma. Although He was doing the same preaching work in His householder life, when He experienced some obstacles to His preaching He sacrificed even the comfort of His home life for the sake of the fallen souls. In His householder life His chief assistants were Śrīla Advaita Prabhu and Śrīla Śrīvāsa Ṭhākura, but after He accepted the sannyāsa order His chief assistants became Śrīla Nityānanda Prabhu, who was deputed to preach specifically in Bengal, and the six Gosvāmīs (Rūpa Gosvāmī, Sanātana Gosvāmī, Jīva Gosvāmī, Gopāla Bhaṭṭa Gosvāmī, Raghunātha dāsa Gosvāmī and Raghunātha Bhaṭṭa Gosvāmī), headed by Śrīla Rūpa and Sanātana, who were deputed to go to Vṛndāvana to excavate the present places of pilgrimage. The present city of Vṛndāvana and the importance of Vrajabhūmi were thus disclosed by the will of Lord Śrī Caitanya Mahāprabhu.
(Srimad Bhagavatam-------introduction).

Śrī Caitanya Mahāprabhu further advised the brāhmaṇa Kūrma, "If you follow this instruction, your materialistic life at home will not obstruct your spiritual advancement. Indeed, if you follow these regulative principles, we will again meet here, or, rather, you will never lose My company."
This is an opportunity for everyone. If one simply follows the instructions of Śrī Caitanya Mahāprabhu, under the guidance of His representative, and chants the Hare Kṛṣṇa mantra, teaching everyone as far as possible the same principle, the contamination of the materialistic way of life will not even touch him. It does not matter whether one lives in a holy place like Vṛndāvana, Navadvīpa or Jagannātha Purī or in the midst of European cities, where the materialistic way of life is very prominent. If a devotee follows the instructions of Śrī Caitanya Mahāprabhu, he lives in the company of the Lord. Wherever he lives, he converts that place into Vṛndāvana and Navadvīpa. This means that materialism cannot touch him. This is the secret of success for one advancing in Kṛṣṇa consciousness.
(Sri Caitanya Caritamrta--------2:7:129---------translation and purport).