Originally it was an ancient Christian three-nave basilica, then a Gothic structure, and later an interesting monument of the provincial Baroque. On the main altar is a silver chest of st. Sime from 1380. The chest is of great value. It was ordered by the Hungarian-Croatian Queen Elizabeth for the relic of st. Sime. The chest was made by the jeweler Francis from Milan, based in Zadar. A Roman pillar erected in 1729 is located in the south part of the church, and it is composed of two pillars of the city temple, which until then had been preserved at the Capitol at the Forum.