Watch Online Free on Watchseries. The construction of Hadrian's Wall began in 122AD, to separate the Romans from Barbarians and was built under the direct orders of Emperor Hadrian. Hadrian's wall took over a decade to complete and was built out of stone. The wall is over 73 miles long and marks the northern border of the Roman Province of Britain, running between the North Sea and the Irish Sea. This fascinating program provides a glimpse of military life during the Roman occupation.