The Castello del Buonconsiglio was the residence of the prince-bishops of Trento from the 13th century until Napoleon abolished the principality in 1802 — an unbroken span of nearly six hundred years that left every century's taste recorded in the stonework. The earliest part is the squat Castelvecchio with its drum tower; the most lavish is the Renaissance Magno Palazzo built by Bernardo Cles in the 1530s to host the great church council.
The castle now functions as the main museum of the Trentino region, with collections of medieval art, archaeology, decorative arts, and a permanent display on the Council of Trent itself. The frescoes are the highlight: rooms by Romanino, Dosso Dossi, and Marcello Fogolino in the Magno Palazzo, and the spectacular Cycle of the Months in the Torre Aquila (separate ticket; numbers strictly limited).