The palace was built between 1244–1246 as an exten­sion of the near­by Palaz­zo del Podestà. It takes its name from Enzio of Sar­dinia, Fred­er­ick II’s son, who was pris­on­er here from 1249 until his death in 1272. The cur­rent Goth­ic appear­ance dates from the restora­tion of 1905 due to Alfon­so Rub­biani.