14. Who designed Hadrian’s Wall?

The simple answer is we do not know, although it is usually assumed that the Emperor Hadrian was involved in some way, during his visit to Britain in AD 122. The basic design was repeatedly modified, suggesting that experience on the ground revealed flaws in the original overall design.

The fact that there were minor differences in detail, such as the forms of milecastle gateways, may indicate individual legions interpreting an overall brief in their own way.

Further reading: Breeze and Dobson 2000