Legend of Udayanapuram Subrahmanya Temple
There is an interesting legend about the interchange of deities at Udayanapuram and Kumaranallur. The former temple was actually intended for Bhagawati and hence was originally known as Udayanayakeepuram while the latter was to be the abode of Kumara or Subrahmanya. It is said that it was the Goddess who intruded into the temple originally intended for Subrahmanya. Hence that temple was named Kumaran-alla-ooru meaning not for Kumara (Subrahmanya).
Similarly with the change of deity at Udayanapuram, Udayanayakeepuram originally meant for the Goddess came to be known as Udayanapuram. The fact that Bhagawati seva (an offering in the form of Bhagawati worship) is still conducted as offering at Udayanapuram confirms the fact that the temple was in fact meant for the Goddess.