The Piarist Convention included a church, a monastery and a school. The postpiarist complex featres the church of St. Cross in the centre, built between 1644-1649 according to the design of Tylman of Gameren. It is a one-nave temple with two towers in the facade and a chapel on the north side. Late baroque decor with stucco decorations by Jan Ch. Falconi from the end of the 17th century. In the chancel, at the entrance to the sacristy, there is a mausoleum of the Lubomirskis family.
In the monastery building there is now the Regional Museum, with rich collections in the fields of art, history, ethnography and archaeology, exhibited in the form of permanent exhibitions (e.g. Galeria Dąbskich) or temporary exhibitions. In the old refectory you can see frescoes from the end of the 17th century.
The Piarists founded the Collegium Ressoviense next to the monastery in 1658. Fr. Stanislaw Konarski taught here - currently the patron of Secondary School No. 1. The school is one of the oldest in Poland. Many of its students were glorified on the pages of Polish history and in culture. Ignacy Łukasiewicz, Jozef S. Pelczar, Wladyslaw Sikorski, Władysław Szafer or Julian Przyboś.