In the book known as Adhyātma-rāmāyaṇa, there are statements in Chapters Twelve to Fifteen about the worship of the Deities Śrī Rāmacandra and Sītā. There it is stated that during Lord Rāmacandra's time there was a brāhmaṇa who took a vow to fast until he saw Lord Rāmacandra. Sometimes, due to business, Lord Rāmacandra was absent from His capital for a full week and could not be seen by citizens during that time. Because of his vow, the brāhmaṇa could not take even a drop of water during that week. Later, after eight or nine days, when the brāhmaṇa could see Lord Rāmacandra personally, he would break his fast. Upon observing the brāhmaṇa's rigid vow, Lord Śrī Rāmacandra ordered His younger brother Lakṣmaṇa to deliver a pair of Sītā-Rāma Deities to the brāhmaṇa. The brāhmaṇa received the Deities from Śrī Lakṣmaṇajī and worshiped Them faithfully as long as he lived.
(above,Named Ram Moola) At the time of his death, he delivered the Deities to Śrī Hanumānjī, who, for many years, hung Them around his neck and served Them with all devotion. After many years, when Hanumānjī departed on the hill known as Gandha-mādana, he delivered the Deities to Bhīmasena, one of the Pāṇḍavas, and Bhīmasena brought Them to his palace, where he kept Them very carefully. The last king of the Pāṇḍavas, Kṣemakānta, worshiped the Deities in that palace. Later, the same Deities were kept in the custody of the kings of Orissa known as Gajapatis. One of the ācāryas, known as Narahari Tīrtha, who was in the disciplic succession of Madhvācārya, received these Deities from the King of Orissa. It may be noted that these particular Deities of Rāma and Sītā have been worshiped from the time of King Ikṣvāku. Indeed, they were worshiped by the royal princes even before the appearance of Lord Rāmacandra. Later, during Lord Rāmacandra's presence, the Deities were worshiped by Lakṣmaṇa. It is said that just three months before his disappearance, Śrī Madhvācārya received these Deities and installed them in the Uḍupī temple. Since then the Deities have been worshiped by the Madhvācārya-sampradāya at that monastery. As far as the Śrī Vaiṣṇavas are concerned, beginning with Rāmānujācārya, they also worshiped Deities of Sītā-Rāma. Sītā-Rāma Deities are also being worshiped in Tirupati and other places. From the Śrī Rāmānuja-sampradāya there is another branch known as Rāmānandī or Rāmāt, and the followers of that branch also worship Deities of Sītā-Rāma very rigidly. The Rāmānuja-sampradāya Vaiṣṇavas prefer the worship of Lord Rāmacandra to that of Rādhā-Kṛṣṇa.Cc. Madhya-lila : Madhya 9: Lord Sri Caitanya Mahaprabhu's Travels to the Holy Places : Madhya 9.11
(The Story connected with below Krsna Deity)
.... Once, while sitting beside the sea engrossed in meditation upon Lord Śrī Kṛṣṇa, he (Madhvacarya) saw that a large boat containing goods for Dvārakā was in danger. He gave some signs by which the boat could approach the shore, and it was saved. The owners of the boat wanted to give him a present, and at the time Madhvācārya agreed to take some gopī-candana. He received a big lump of gopī-candana, and as it was being brought to him, it broke apart and revealed a large Deity of Lord Kṛṣṇa. The Deity had a stick in one hand and a lump of food in the other. As soon as Madhvācārya received the Deity of Kṛṣṇa in this way, he composed a prayer. The Deity was so heavy that not even thirty people could lift it. Madhvācārya personally brought this Deity to Uḍupī. Madhvācārya had eight disciples, all of whom took sannyāsa from him and became directors of his eight monasteries. Worship of the Lord Kṛṣṇa Deity is still going on at Uḍupī according to the plans Madhvācārya established.....
Most of the information in this purport is available from the South Kānāḍā Manual and the Bombay Gazette.
Sri Caitanya-caritamrta - 1975 Edition : Cc. Madhya-lila : Madhya 9: Lord Sri Caitanya Mahaprabhu's Travels to the Holy Places : Madhya 9.245