Thanks. I've seen this piece. I picked up a book off Amazon called Images in Ivory. It was an exhibition the Detroit Institute of Arts focused on ivory carvings and their history and context. Highly recommended.
https://www.amazon.com/Images-Ivory-Precious-Objects-Gothic/dp/0691016119?keywords=images+in+ivory&qid=1537891393&sr=8-2&ref=mp_s_a_1_2