Iran is the apparent birthplace of the earliest complex instruments, dating back to the third millennium BC. The use of both vertical and horizontal angular harps have been documented at the sites Madaktu and Kul-e Farah, with the largest collection of Elamite instruments documented at Kul-e Farah. Multiple depictions of horizontal harps were also sculpted in Assyrian palaces, dating back between 865 and 650 BC.