Panchayatana puja (IAST ) is the system of worship ('puja') in the Smarta sampradaya of Hinduism. It is said to have been introduced by Adi Shankara, the 8th century CE Hindu philosopher. It consists of the worship of five deities: Shiva, Vishnu, Devi or Durga, Surya and Ganesha. Depending on the tradition followed by Smarta households, one of these deities is kept in the center and the other four surround it. Worship is offered to all the deities. The five are represented by small murtis, or by five kinds of stones called a Panchayatana puja set, or by five marks drawn on the floor. One is placed in the center as the devotee's preferred God, Ishta Devata, and the other four in a square around it.