According to the Vaiṣṇava almanac, the twelve months of the year are named according to the twelve Vaikuṇṭha forms of Lord Kṛṣṇa, and these forms are known as the predominating Deities for the twelve months. This calendar begins with the month of Mārgaśīrṣa, which is equivalent to late November and early December. The Vaiṣṇavas call this month Keśava. December–January is called Nārāyaṇa, January–February Mādhava, February–March Govinda, March–April Viṣṇu, April–May Śrī Madhusūdana, and May–June Trivikrama. June–July is called Vāmana, July–August Śrīdhara, August–September Hṛṣīkeśa, September–October Padmanābha, and October–November Dāmodara. This Dāmodara is different from the Dāmodara in Vraja. The name Dāmodara was given to Kṛṣṇa when He was bound with ropes by His mother, but the Dāmodara form who is the predominating Deity of the month of October–November is a different manifestation.
Just as the months of the year are known according to the twelve different names of the Supreme Lord, members of the Vaiṣṇava community mark twelve parts of the body according to these names. For instance, the tilaka mark on the forehead is called Keśava, and on the stomach, chest and arms the other names are also given. These are the same names as those given the months.
Vāsudeva, Saṅkarṣaṇa, Pradyumna and Aniruddha expand in eight additional vilāsa-mūrtis. Their names are Puruṣottama, Acyuta, Nṛsiṁha, Janārdana, Hari, Kṛṣṇa, Adhokṣaja and Upendra. Adhokṣaja and Puruṣottama are the vilāsa forms of Vāsudeva. Similarly, Upendra and Acyuta are the vilāsa forms of Saṅkarṣaṇa; Nṛsiṁha and Janārdana the vilāsa forms of Pradyumna; and Hari and Kṛṣṇa the vilāsa forms of Aniruddha. (This Kṛṣṇa is different from the original Kṛṣṇa.)
These twenty-four forms—the four original Viṣṇu forms, the twelve Vaikuṇṭha forms, and the eight vilāsa-mūrtis mentioned above—are known as vilāsa manifestations of the prābhava (four-handed) form, and they are named differently according to the position of the symbolic representations (mace, disc, lotus flower and conch shell). Out of these twenty-four vilāsa forms, some are vaibhava forms, such as Pradyumna, Trivikrama, Vāmana, Hari and Kṛṣṇa, which have different features. Thus Vāsudeva, Saṅkarṣaṇa, Pradyumna and Aniruddha are prābhava-vilāsa forms of Kṛṣṇa, and there are a total of twenty further variations. All of these have Vaikuṇṭha planets in the spiritual sky and are situated in eight different directions. Although each of them resides eternally in the spiritual sky, some of them nonetheless appear in the material world also.
In the spiritual sky all the planets dominated by the Nārāyaṇa feature are eternal. The topmost planet in the spiritual sky is called Kṛṣṇaloka, which is divided into three portions: Gokula, Mathurā and Dvārakā. In the Mathurā portion, the form of Keśava is always situated. He is represented on this earthly planet in Mathurā, India, where the Keśava mūrti is worshiped. Similarly, there is a Puruṣottama form in Jagannātha Purī, in Orissa. In Ānandāraṇya there is the form of Viṣṇu, and in Māyāpur, the birthplace of Lord Caitanya, there is the form of Hari. Many other forms are also situated in various places on the earth.
Not only in this universe but in all other universes as well these forms of Kṛṣṇa are distributed everywhere. It is indicated that this earth is divided into seven islands, which are the seven continents, and it is understood that on every island there are similar forms. But at the present moment these are found only in India. Although from the Vedic literature we can understand that there are similar forms in other parts of the world, at present there is no information of their location.
These forms of Kṛṣṇa are distributed throughout the world and throughout the universes to give pleasure to the devotees. It is not that devotees are born only in India. There are devotees in all parts of the world, but they have simply forgotten their identity. These forms incarnate not only to give pleasure to the devotees but to reestablish devotional service and perform other activities which vitally concern the Supreme Personality of Godhead. Some of these forms are incarnations mentioned in the scriptures, such as the Viṣṇu incarnation, Trivikrama incarnation, Nṛsiṁha incarnation and Vāmana incarnation.
In the Siddhārtha-saṁhitā there is a description of the twenty-four forms of Viṣṇu, and these forms are named according to the position of the symbols in Their four hands. When describing the positions of objects in the hands of the Viṣṇu mūrtis, one should begin with the lower right hand and then move to the upper right hand, to the upper left hand and finally to the lower left hand. In this way, Vāsudeva is represented by club, conch shell, disc and lotus flower. Saṅkarṣaṇa is represented by club, conch shell, lotus flower and disc. Similarly, Pradyumna is represented by disc, conch shell, club and lotus flower. Aniruddha is represented by disc, club, conch shell and lotus flower. In the spiritual sky the representations of Nārāyaṇa are twenty in number and are described as follows: Śrī Keśava (lotus, conch shell, disc and club), Nārāyaṇa (conch, lotus, club and disc), Śrī Mādhava (club, disc, conch and lotus), Śrī Govinda (disc, club, lotus and conch), Viṣṇu-mūrti (club, lotus, conch and disc), Madhusūdana (disc, conch, lotus and club), Trivikrama (lotus, club, disc and conch), Śrī Vāmana (conch, disc, club and lotus), Śrīdhara (lotus, disc, club and conch), Hṛṣīkeśa (club, disc, lotus and conch), Padmanābha (conch, lotus, disc and club), Dāmodara (lotus, disc, club and conch), Puruṣottama (disc, lotus, conch and club), Acyuta (club, lotus, disc and conch), Nṛsiṁha (disc, lotus, club and conch), Janārdana (lotus, disc, conch and club), Śrī Hari (conch, disc, lotus and club), Śrī Kṛṣṇa (conch, club, lotus and disc), Adhokṣaja (lotus, club, conch and disc), and Upendra (conch, club, disc and lotus).
According to the Hayaśīrṣa-pañcarātra, there are sixteen forms, and these are also named according to the positions of the disc and so on. The conclusion is that the Supreme Original Personality of Godhead is Kṛṣṇa. He is called līlā-puruṣottama, and He resides principally in Vṛndāvana as the son of Nanda. It is also learned from the Hayaśīrṣa-pañcarātra that there are nine forms protecting the two Purīs known as Mathurā Purī and Dvārakā Purī. These nine forms are Vāsudeva, Saṅkarṣaṇa, Pradyumna, Aniruddha, Nārāyaṇa, Nṛsiṁha, Hayagrīva, Varāha and Brahmā. These are different manifestations of the prakāśa and vilāsa forms of Lord Kṛṣṇa.
Lord Caitanya next informed Sanātana Gosvāmī that there are different forms of svāṁśa as well, and these are divided into the Saṅkarṣaṇa division and the incarnation division. The Saṅkarṣaṇa division includes the three puruṣa-avatāras—Kāraṇodakaśāyī Viṣṇu, Garbhodakaśāyī Viṣṇu and Kṣīrodakaśāyī Viṣṇu—and the other division comprises the līlā-avatāras, such as the Lord's incarnations as a fish and a tortoise.
There are six kinds of incarnations: (1) the puruṣa-avatāras, (2) the līlā-avatāras, (3) the guṇa-avatāras, (4) the manvantara-avatāras, (5) the yuga-avatāras and (6) the śaktyāveśa-avatāras. Out of the six vilāsa manifestations of Kṛṣṇa, there are two divisions based on His age, and these are called bālya and paugaṇḍa. As the son of Nanda Mahārāja, Kṛṣṇa in His original form enjoys both of these childhood aspects—namely bālya and paugaṇḍa.
We can conclude that there is no end to the expansions and incarnations of Kṛṣṇa. Lord Caitanya described some of them to Sanātana just to give him an idea of how the Lord expands and how He enjoys. These conclusions are confirmed in Śrīmad-Bhāgavatam (1.3.26). There it is said that there is no limit to the incarnations of the Supreme Lord, just as there is no limit to the waves of the ocean.
Kṛṣṇa first incarnates as the three puruṣa-avatāras, namely the Mahā-viṣṇu or Kāraṇodakaśāyīavatāra, the Garbhodakaśāyīavatāra and the Kṣīrodakaśāyīavatāra. This is confirmed in the Sātvata-tantra. Kṛṣṇa's energies can also be divided into three: His energy of thinking, His energy of feeling, and His energy of acting. When He exhibits His thinking energy He is the Supreme Lord, when He exhibits His feeling energy He is Lord Vāsudeva, and when He exhibits His acting energy He is Saṅkarṣaṇa Balarāma. Without the Lord's thinking, feeling and acting, there would be no possibility of creation. Although there is no creation in the spiritual world as there is in the material world, both worlds are manifestations of Kṛṣṇa's energy of acting, which He carries out in the form of Saṅkarṣaṇa Balarāma.
The spiritual world—the Vaikuṇṭha planets and Kṛṣṇaloka—is situated in Kṛṣṇa's energy of thinking. Although there is no creation in the spiritual world, which is eternal, it is still to be understood that the spiritual planets depend on the thinking energy of the Supreme Lord. This thinking energy is described in the Brahma-saṁhitā (5.2), where it is said, "The supreme abode, known as Goloka, is manifested like a lotus flower with hundreds of petals. Everything there is manifested by Ananta, who is a form of Balarāma, or Saṅkarṣaṇa." The material cosmic manifestation and its different universes are manifested through māyā, or the material energy, but one should not think that the material energy, or material nature, is the cause of this cosmic manifestation. Rather, it is caused by the Supreme Lord, who uses His different expansions to act through material nature. In other words, there is no possibility of any creation without the superintendence of the Supreme Lord. The form of the Lord who causes the energy of material nature to bring about creation is Saṅkarṣaṇa, and it is understood that this cosmic manifestation is created when the material nature comes in contact with the superintendent energy of the Supreme Lord, Saṅkarṣaṇa. The example is given of iron becoming hot in contact with fire and, when red hot, acting just like fire.
In Śrīmad-Bhāgavatam (10.46.31) it is said that Balarāma and Kṛṣṇa are the origin of all living entities and that these two personalities enter into everything. A list of incarnations is given in Śrīmad-Bhāgavatam (1.3), and they are as follows: (1) the Kumāras, (2) Nārada, (3) Varāha, (4) Matsya, (5) Yajña, (6) Nara-Nārāyaṇa, (7) Kārdami Kapila, (8) Dattātreya, (9) Hayaśīrṣa, (10) Haṁsa, (11) Dhruvapriya, or Pṛśnigarbha, (12) Ṛṣabha, (13) Pṛthu, (14) Nṛsiṁha, (15) Kūrma, (16) Dhanvantari, (17) Mohinī, (18) Vāmana, (19) Bhārgava (Paraśurāma), (20) Rāghavendra, (21) Vyāsa, (22) Pralambāri Balarāma, (23) Kṛṣṇa, (24) Buddha and (25) Kalki. Because almost all of these twenty-five līlā-avatāras appear in one day of Brahmā, which is called a kalpa, they are sometimes called kalpa-avatāras. Out of these incarnations, Haṁsa and Mohinī are not permanent, but Kapila, Dattātreya, Ṛṣabha, Dhanvantari and Vyāsa are five eternal forms, and they are more celebrated. Kūrma (the tortoise incarnation), Matsya (the fish), Nara-Nārāyaṇa, Varāha (the boar), Hayaśīrṣa, Pṛśnigarbha and Balarāma are considered incarnations of vaibhava. Similarly, there are three guṇa-avatāras, or incarnations of the qualitative modes of nature, and these are Brahmā, Viṣṇu and Śiva.
There are fourteen manvantara-avatāras: (1) Yajña, (2) Vibhu, (3) Satyasena, (4) Hari, (5) Vaikuṇṭha, (6) Ajita, (7) Vāmana, (8) Sārvabhauma, (9) Ṛṣabha, (10) Viṣvaksena, (11) Dharmasetu, (12) Sudhāmā, (13) Yogeśvara and (14) Bṛhadbhānu. Out of these fourteen manvantara-avatāras, Yajña and Vāmana are also līlā-avatāras. The manvantara-avatāras are also known as vaibhava-avatāras.
The four yuga-avatāras are also described in Śrīmad-Bhāgavatam. In the Satya-yuga the incarnation of God is white; in the Tretā-yuga He is red; in the Dvāpara-yuga He is blackish; and in the Kali-yuga He is also blackish, but sometimes, in a special Kali-yuga, His color is yellowish (as in the case of Caitanya Mahāprabhu). As far as the śaktyāveśa-avatāras are concerned, they include Kapila, Ṛṣabha, Ananta, Brahmā (although sometimes the Lord Himself becomes Brahmā), Catuḥsana (the Kumāras, who are the incarnation of knowledge), Nārada (the incarnation of devotional service), King Pṛthu (the incarnation of administrative power) and Paraśurāma (the incarnation who subdues evil principles).