 He proclaimed as Augusti (co-emperors) his elder son Caracalla in 198 and his younger son Geta in 209, both born of his second wife Julia Domna.Severus travelled to Britain in 208, strengthening Hadrian's Wall and reoccupying the Antonine Wall.In AD 209 he invaded Caledonia (modern Scotland) with an army of 50,000 men but his ambitions were cut short when he fell fatally ill of an infectious disease in late 210.