During this period, the city was autonomously ruled by a ''senatore'' or ''patrizio''. In the 12th century, this administration, like other European cities, evolved into the commune, a new form of social organisation controlled by the new wealthy classes. Pope Lucius II fought against the Roman commune, and the struggle was continued by his successor Pope Eugenius III: by this stage, the commune, allied with the aristocracy, was supported by Arnaldo da Brescia, a monk who was a religious and social reformer. After the pope's death, Arnaldo was taken prisoner by Adrianus IV, which marked the end of the commune's autonomy. Under Pope Innocent III, whose reign marked the apogee of the papacy, the commune liquidated the senate, and replaced it with a ''Senatore'', who was subject to the pope.