CC Ādi 2.81

taiche kṛṣṇa avatāra-bhitare haila jñāta
tāṅhāra viśeṣa-jñāna sei avijñāta
Word for word: 
taiche — in the same way; kṛṣṇa — Lord Kṛṣṇa; avatāra-bhitare — among the incarnations; haila — was; jñāta — known; tāṅhāra — of Him; viśeṣa-jñāna — specific knowledge; sei — that; avijñāta — unknown.
Translation: 
“In the same way, when Kṛṣṇa was first counted among the incarnations, specific knowledge about Him was still unknown.