According to the Chronica S. Benedicti Casinensis, the gastald of Capua, Landulf the Old, who had been an ally of Sicard, freed the imprisoned Siconulf and, with the support of Guaifer, chief of the Dauferidi family of Salerno, brought him to that city to be proclaimed prince in opposition to Radelchis.
In 841, Radelchis brought in the aid of Gargliano Siculos, as Andrew II of Naples had four years prior.
The mercenaries sacked the city of Capua, forcing Landulf to found a new capital nearby on the hill of Triflisco.
The depredations of the two Christian rulers and their Saracen helpers so disturbed the king of Italy, Louis II, that when he was crowned co-emperor in 850, he immediately set out to pacify the Mezzogiorno.
In 851, Louis forced a peace on Radelchis and Siconulf and started expelling the Sicillian Emirs from Italy.