(turkish: ayasofya) a cathedral built in the 6th century in modern-day istanbul, turkey. constructed under the direction of byzantine emperor justinian i, it is considered one of, if not the most significant byzantine monuments. it stands today as a symbol of the religious developments that have taken place throughout the ages in this city. presenting elements of both islam and christianity alike, it started as an orthodox christian temple and was converted to a muslim mosque after the ottoman conquest in 1543. it was converted to a museum and named a unesco world heritage site in 1934, and has since been converted back to a mosque.
