CC Madhya 25.208

māsa-mātra rūpa-gosāñi rahilā vṛndāvane
śīghra cali’ āilā sanātanānusandhāne
Word for word: 
māsa-mātra — only one month; rūpa-gosāñi — Rūpa Gosāñi; rahilā — remained; vṛndāvane — at Vṛndāvana; śīghra — very soon; cali’ āilā — returned; sanātana-anusandhāne — to search for Sanātana Gosvāmī.
Translation: 
Rūpa Gosvāmī remained in Mathurā and Vṛndāvana for one month in the association of Subuddhi Rāya. After that, he left Vṛndāvana to search for his elder brother, Sanātana Gosvāmī.