As well as rebuilding the Pantheon, this man built a namesake wall during his conquests in Great Britain.
This man was never actually named emperor by his predecessor, but rather by that predecessor's wife, Plotina. One of this man's first actions was to put down a possible rebellion led by Lucius Quietus. His namesake mausoleum later became known as the Castel Sant' Angelo. This man abandoned his predecessor's conquests in Mesopotamia for fear that they could not be defended. As well as rebuilding the Pantheon, this man built a namesake wall during his conquests in Great Britain. For 10 points, name this Roman Emperor, the successor to Trajan and predecessor to Antoninus Pius.
This man was never actually named emperor by his predecessor, but rather by that predecessor's wife, Plotina.
{Hadrian} or {Publius Aelius Hadrianus}