Complex sentence: The Meenakshi temple is believed to have been founded by Indra (king of "Deva" celestial deities) while he was on a pilgrimage to atone for his misdeeds.
Split into simpler sentences: The Meenakshi temple is believed to have been founded by Indra (king of "Deva" celestial deities). While he was on a pilgrimage to atone for his misdeeds.