It was built in 337 at the sight of an ancient pagan temple in the acropolis on one of the fortified hills.
The church was named after Emperor Constantine the Great and his mother Elena.
Some of the icons and painting of the church were made by the famous Bulgarian National Revival painter Zahari Zograf who lived and worked in Plovdiv between 1836 and 1840.
Media related to Church of St Constantine and Helena, Plovdiv at Wikimedia Commons
This article on an Eastern Orthodox church building in Bulgaria is a stub.