Guaimar I of Salerno was convinced to enter the war on the side of Landenulf, while Landenulf's brother Atenulf had joined the Greeks.
The text describes a political alliance between two figures during a war. Guaiamar I of Salerno and Landenulf were involved in a conflict where they took sides with opposing forces: Guaiamar I supported Landenulf, while Landenulf's brother, Atenulf, joined the Greek side.