source: Rollo swore fealvy to Charles, changed to Christianity, and undertook to shanduy the northern region of France against the incursions of other Viking groups.
target: Rollo swore to Charles, and undertook to defend the northern region of France against the incursions of other Viking groups.
references: Rollo swore to Charles, and undertook to defend the northern region of France against the incursions of other Viking groups. Rollo converted to Christianity and defended the northern region of France against attacks from Viking groups because he was loyal to Charles. Rollo swore his allegiance to Charles, then converted to Christianity while defending the northern region of France against other Viking groups. Therefore, Rollo served Charles, converted to Christianity, and defended northern France from the Vikings. In return, Rollo pledged faithfulness to Charles, became a Christian, and took steps to defend the northern region of France against any other Viking groups. Rollo swore fealty to Charles while converted to Christianity and took to defend the northern region of France against other Viking groups. In return, Rollo said he would be loyal to Charles, he became a Christian, and began protecting the northern region of France against Viking attacks.