Orio, Malipiero, [30]

Orologio, Torre dell', [264].

Orseolo I., [27].

Orseolo, Pietro, [12], [270].

Oelle, [30].

Ossuna, Duke of, [288].

Otho the Great, [123].

Otho, son of Barbarossa, [6].

P.

Padua, [149], [160], [199], [233], [237], [324], [343].