CC Madhya 18.47

mleccha-bhaye āilā gopāla mathurā-nagare
eka-māsa rahila viṭhṭhaleśvara-ghare
Word for word: 
mleccha-bhaye — because of fear of the Muslims; āilā — came; gopāla — the Gopāla Deity; mathurā-nagare — to the city of Mathurā; eka-māsa — one month; rahila — stayed; viṭhṭhaleśvara-ghare — in the house of Viṭhṭhaleśvara.
Translation: 
Due to fear of the Muslims, Gopāla went to Mathurā, where He remained in the house of Viṭhṭhaleśvara for one full month.
Purport: 

When the two brothers Śrīla Rūpa Gosvāmī and Sanātana Gosvāmī went to Vṛndāvana, they decided to live there. Following Śrī Caitanya Mahāprabhu’s example, they did not climb the hill because they considered it nondifferent from Kṛṣṇa, the Supreme Personality of Godhead. On some pretext, the Gopāla Deity granted Śrī Caitanya Mahāprabhu an audience beneath the hill, and Gopāla similarly favored Śrīla Rūpa Gosvāmī and Sanātana Gosvāmī. During his ripe old age, when Rūpa Gosvāmī could not go to Govardhana Hill because of invalidity, Gopāla kindly went to Mathurā and remained at the house of Viṭhṭhaleśvara for one month. It was then that Śrīla Rūpa Gosvāmī could see Gopāla’s beauty to his heart’s content.

The following description concerning Viṭhṭhaleśvara is given in the Bhakti-ratnākara (Fifth Wave):

viṭhṭhalera sevā kṛṣṇa-caitanya-vigraha
tāhāra darśane haila parama āgraha

śrī-viṭhṭhalanātha — bhaṭṭa-vallabha-tanaya
karilā yateka prīti kahile nā haya

gāṭholi-grāme gopāla āilā ‘chala’ kari’
tāṅre dekhi’ nṛtya-gīte magna gaurahari

śrī-dāsa-gosvāmī ādi parāmarśa kari’
śrī-viṭhṭhaleśvare kailā sevā-adhikārī

pitā śrī-vallabha-bhaṭṭa tāṅra adarśane
kata-dina mathurāya chilena nirjane

Śrī Vallabha Bhaṭṭa had two sons. The elder, Gopīnātha, was born in 1432 Śakābda Era (A.D. 1510), and the younger, Viṭhṭhaleśvara, was born in 1437 (A.D. 1515) and died in 1507 (A.D. 1585). Viṭhṭhaleśvara had seven sons: Giridhara, Govinda, Bālakṛṣṇa, Gokuleśa, Raghunātha, Yadunātha and Ghanaśyāma. Viṭhṭhaleśvara completed many of his father’s unfinished books, including his commentary on the Vedānta-sūtra, the Subodhinī commentary on Śrīmad-Bhāgavatam, Vidvan-maṇḍana, Śṛṅgāra-rasa-maṇḍana and Nyāsādeśa-vivaraṇa. Śrī Caitanya Mahāprabhu went to Vṛndāvana before the birth of Viṭhṭhaleśvara. As previously mentioned, Śrīla Rūpa Gosvāmī was very old at the time Gopāla stayed at the house of Viṭhṭhaleśvara.