The Casa del Doncel is a handsome late-medieval house associated with the Vázquez de Arce family, whose young knight Martín became the famous Doncel buried in the cathedral. Its facade is restrained rather than flashy, but the stonework and interior courtyards make it one of the most evocative domestic buildings in town.
Inside, exhibitions usually focus on local history, archaeology, and the cultural life of Sigüenza. It is worth visiting before the cathedral tomb if you want the Doncel to feel like a person from a particular family and street, not just a beautiful sculpture.