flee, and allied with the king and the Neustrians. Outside of Cologne, held by Plectrude, an ill-prepared Charles Martel was defeated by Redbad, and forced to flee to the mountains of the Eifel. Cologne fell after a short siege to Chilperic, the Frisians and the Neustrians. Once in the mountains of the Eifel, Charles began to rally his supporters, and in short order was ready to do battle. Many Austrasians, under attack by Neustrians, Frisians, and Saxons in the northeast likely rallied behind Martel because he was the only surviving adult male of the Pippinnid family. His forces then attacked the army of Chilperic II and his allies at the Battle of Amblève near Amel as they returned triumphantly from Cologne. Martel used a feigned retreat, falling on his foes as they rested at midday, and feigning falling back to draw them fully out of a defensive position, where he defeated them, devastating the Frisian army. Willibrord was then joined by Boniface, an Anglo-Saxon bishop. They spent a year together attempting to convert the Frisians to Christianity, but their efforts were frustrated when Redbad retook possession of Frisia, burning churches and killing many missionaries. Willibrord and Boniface were forced to flee to the protection of Charles Martel. The Frisian army returned to the north with a large war loot. Redbad made plans to invade Francia for the second time and mobilised a large army, but before he could do this he died of an illness in 719. It is not certain who the successor of Redbad was. It is believed that there were troubles with the succession, because the Frankish opponent Charles Martel could easily invade Frisia and subjugate the land. The resistance was so weak that Charles Martel not only annexed Frisia Citerior ("nearer" Frisia south of the Rhine), but he also crossed the Rhine and annexed "farther" Frisia, to the banks of the river Vlie. Now protected by the Franks, Willibrord returned to Frisia. Poppo There was a rebellion against Frankish rule in the region of Westergo in 733, which Charles put down. The inhabitants gave hostages, converted to Christianity and recognised Frankish overlordship, but after Charles left they were punished by their fellow Frisians. The next year, the Frisians rebelled again, this time under the leadership of King Poppo. Charles gathered a large fleet and ferried an army across the Almere for a naval invasion. Initial landings