Throughout the Greek and Roman periods, earlier Egyptian musical traditions persisted. This is especially true for religious music, which had a long tradition in Egypt. Temple musicians, who were frequently elite women, performed music to accompany ritual activities. Musicians were also often the center of ritual themselves, as in the duets sung by women disguised as the Egyptian goddesses Isis and Nephthys. The rattle known as the "sistrum" was a quintessentially Egyptian instrument for worship; its use spread throughout the Roman world along with the cult of the Egyptian goddess Isis.