The sistrum was basically a rattle comprising an arch (an inverted U-shaped section) with a handle attached. The arch had a number of cross pieces onto which were threaded metal discs. When the sistrum was shaken, the discs rattled. The top of the handle was often decorated with the head of Hathor, patron of music. The instrument, carried in tomb and temple scenes, indicated devotion to Hathor, and symbolized adoration in general. The similarity between the shape of the sistrum and that of the ankh meant that, like the ankh, it came to represent life.The sistrum was used in Egyptian festivals and was often played by temple songstresses. Shaking the sistrum probably marked the division of the phrases in adulatory hymns. It was believed that the sound of rattling also drove off malign forces, preventing them from spoiling the festival.The sistrum continued to be used in Egypt well after the rule of the pharaohs. By the time of the Greek author Plutarch, around the first or second century AD, the arch of the sistrum had come to symbolise the lunar cycle and the sistrum's bars, the elements. The Hathor heads were interpreted as Isis and Nephthys, who represented life and death respectively. In ceremonies of the Coptic period, priests extended the sistrum to the four cardinal points to indicate the power of god.