The Germanic Franks formed out of a federation of several tribes from the central Rhine area, opposite the Roman Empire in the early 3rd century. Archeological evidence have shown that the Roman fortresses in the lower Rhine were destroyed in the 240s, and rebuild under emperor Decius. This has probably been done by the Franks. Fortress Matilo, which is a few hundred meters away from my home, was abandoned in the early 3rd century, but was temporarily occupied in 243, which could have been done in order for the Romans, to fight the invaders. In 241, the Alamanni invaded the Roman Empire. Maybe the Franks invaded the Roman Empire as well, and raided the lower Rhine area.