In March 1011, the catepan Basil Mesardonites and Leo Tornikios Kontoleon, the strategos of Cephalonia, disembarked with reinforcements from Constantinople.
While Melus fled to Guaimar III of Salerno, Dattus looked to the protection of the Abbey of Montecassino, where he was aided by the Latin monks, and to Pope Benedict VIII, who loaned him papal troops to garrison a tower on the Garigliano, in the territory of the Duchy of Gaeta, then ruled by the anti-Byzantine Emilia.
In 1020, while Melus was conferencing with pope and the German king in Bamberg, the new catepan, Basil Boioannes, and his new ally, Pandulf IV of Capua, marched on the tower and took it.
At Bari on 15 June 1021, Dattus was tied up in a sack with a monkey, a rooster, and a snake and tossed into the sea (the so-called mazzeratura [it], similar to the ancient Roma Poena cullei).
The atrocity prompted a quick Western response; a huge army under the Emperor Henry II marched south to besiege the new fortress of Troia.