The Anglo-Saxons were able to invade England so easily because the native Celtic inhabitants of the island were not unified and did not have a strong military force to defend themselves against the invaders. The Celts were divided into numerous small kingdoms, which made it difficult for them to coordinate a unified defense against the Anglo-Saxons. Additionally, the Anglo-Saxons had superior naval technology and were able to cross the English Channel with relative ease. Finally, the Anglo-Saxons had a long history of warfare, which gave them a significant advantage over the Celts.