Complex sentence: It was an announcement by Sri Chaitanya Mahaprabhu inviting a dear devotee of His into a very special family of His personal associates, and practically unheard of in the history of transcendence, a child is announced directly by the Supreme personality of Godhead.
Split into simpler sentences: It was an actual announcement by Sri Chaitanya Mahaprabhu inviting a dear devotee of His into a very special family of His personal associates. And practically unheard of in the history of transcendence, a child is announced directly by the Supreme personality of Godhead.