At that time this Vṛndāvana, which you have seen, now it is nice city, but during the time of Caitanya Mahāprabhu it was a big field only, that's all, nothing more than that. Everything, all Kṛṣṇa's līlā were vanished. Not vanished; it was not visible. Caitanya Mahāprabhu saw one small hole, little water, and He indicated, "This is Rādhā-kuṇḍa." Then Rādhā-kuṇḍa was discovered. So these Gosvāmīs, they were working very hard.
And special business was there, nana-śāstra-vicaraṇaika-nipunau. They were very expert in scrutinizingly studying all the Vedic literatures. Nana-śāstra. Śāstra, not ordinary knowledge. They were also reading. Nana-śāstra-vicaraṇaika-nipunau. Just like Rūpa Gosvāmī has quoted so many verses, so many incidents from different śāstras, how the biography is stated there in compiling Bhakti-rasāmṛta-sindhu, which we have translated, Nectar of Devotion. So this Nectar of Devotion . . . because formerly whatever is given under Vedic evidence, people will accept all it is correct. Therefore nana-śāstra-vicaraṇaika. They used to collect all the Vedic references and put into the Bhakti-rasāmṛta-sindhu to establish that bhagavad-bhakti, devotional service to the Lord, is the ultimate goal of life. Nānā-śāstra-vicāraṇaika-nipuṇau sad-dharma-saṁsthāpakau. Sad-dharma. Not asad-dharma.