In 1020, Boniface defeated a rebellion of his brother Conrad, but the two reconciled and both were later recorded as dukes. In 1027, he supported the candidacy of Conrad II of Germany for the thrones of Italy and the Holy Roman Empire against the other claimants: William V of Aquitaine, Robert II of France, or Hugh Magnus. When Boniface's Lombard enemies tried to incite his brother against him, the two offered battle to them at Coviolo, near Reggio, and emerged victorious, though Conrad was killed. When Conrad II finally succeeded in entering Italy, he was met with defiance at Lucca and he deposed the reigning margrave of Tuscany, Rainier, and gave his lands and titles to Boniface. This seems to be the probable scenario, though the exact date of Boniface's assumption of the Tuscan lordship is uncertain.