Initially, the Church of St Simeon in Zadar was an Early Christian three-nave basilica, then a Gothic building, and later a monument of provincial Baroque characteristics. On its main Altar there is a silver casket with the relics of St Simeon, dating back to 1380.
The Casket of St Simeon is considered to be the most valuable work of Medieval goldsmith art in Croatia, which was ordered by the Hungaro-Croatian Queen Elizabeth for the relics of St Simeon. It was made by the goldsmith Franciscus de Mediolano (of Milan), who was living in Zadar at the time, and in the south of the Church of St Simeon there is a Roman column that was put there from the Forum in 1729, and which is made of two preserved columns from the city temple on the Capitolium.