Giovanni Battista Trevano

He was not alone in this project: Giacomo Rodondo, Paolo del Corte and Mateo Castelli were all involved in remaking the castle into a new Baroque structure, on its imposing site along the bank of the river Vistula.

In Kraków, on the Wawel hill, following a fire in 1595, Trevano rebuilt the state apartments of the Royal Castle for Sigismund III Vasa.

Also on the Wawel hill, in the Cathedral Church of St Wenceslas, which has been repeatedly reconstructed around the 11th-century shrine of St. Stanislaus of Szczepanów, Trevano built the shrine-mausoleum with the crossing dome, supported on four piers (1626–29).

It was designed by Giovanni de Rossi as a cruciform basilica with a domed crossing and completed by Trevano.

In Kielce the bishop's palace, built 1637–41 for Jakub Zadzik as a personal monument, is undocumented but is attributed to Trevano, though Tomasso Poncino, another Italian working in Poland but mainly as a building contractor, is credited with carrying out the construction and working out some of the architectural detail.