In 1459, Ferdinand's rule was threatened by a long revolt of the barons. Among the leaders of revolt were the prince of Taranto, uncle of Ferdinand's wife. The rebels joined to offer the crown to John of Anjou, a son of the former king René. With the help of the Genoese, John brought a fleet and landed, slowly taking some towns including Nocera. On July 7, 1460, Ferdinand was defeated by John in the plain beside the mouth of the Sarno River south of Mount Vesuvius. Ferdinand was nearly captured and escaped with a guard of only twenty men. The pope and the duke of Milan sent reinforcements under the count of Urbino Federico da Montefeltro and condottiero Alessandro Sforza, but these arrived after the defeat and were themselves crushed by John's ally Piccinino at San Fabriano.