Chidambaram / Hari Hara Stuti

http://en.wikipedia.org/wiki/Thillai_Nataraja_Temple,_Chidambaram#Legend

Sri Appayya Dikshita who had no distinction between Siva and Vishnu wrote the Harihara Stuti. This contains ten verses. In each both Siva and Vishnu are praised alternatively. It is well-known that in Chidambaram one can have darshan of both the Lords at the same time.