<prompt> Translate the following text to EnglishJengo la sasa linategemea jengo la karne ya nne ambalo linasemekana lilitengenezwa kwa agizo la Mtakatifu Helena, mama wa Konstantino Mkuu mwanzilishi wa Constantinople na kiongozi aliyegeuza Milki ya Kirumi kuwa Ukristo, na kanisa la karne ya sita linatumia nguzo kutoka kwa hekalu la kale la Kirumi.  <response>: The present buildings are based around a fourth-century structure that is said to have been commissioned by St. Helen, mother of Constantine the Great founder of Constantinople and the leader who converted the Roman Empire to Christianity, and the sixth-century chapel uses columns from an earlier Roman temple. 