Cross of Canterbury (Accepted)
The “cross of Canterbury” was first found as a piece of jewelry, dating from the 8th or 9th Century, excavated in 1867 in St. George’s Street, Canterbury (and now in the Royal Museum). The design was later carved into the wall of Canterbury Cathedral (SW Transept). It is the symbol of that religious house.
Sebastian de Grey bears: Purpure, an owl close affronty and on a chief argent three crosses of Canterbury purpure.
Ginevra Isabella di Serafino Visconti bears as a badge: A Canterbury cross argent.