Louis I, known as Louis the Pious 778-840
King of Aquitaine, King of the Franks and Emperor of the Western or Carolingian Empire

Born near Poitiers, he was the sole surviving son of Charlemagne. He was King of Aquitaine from 781 to 814, and Carolingian Emperor from 814 until his death. In 817 he attempted to secure his succession by dividing his territories between his three sons, Lothair (d.855), Pepin (d.838) and Louis 'the German' (d.876), with Lothair to be the emperor. In 829 a further share was given to a fourth son, Charles the Bald (Charles I of France). Louis I collaborated with St Benedict of Aniane to reform the Church, was a distinguished patron of scholarship, and defended the north-west from the raids of the Norsemen. It is greatly debated how far the proliferation of hereditary countships and of the institutions of vassalage, often thought to result from these raids, caused a general decline in imperial authority. After his death the empire disintegrated as his sons fought for supremacy.