The Serbian Constantius I was the second emperor to die in York (Eboracum) while fighting the tribes from Scotland. His complete history is on wikipedia under the name Constantius Chlorus ( he only became Constantius I after the second was on the throne).
In the year 286 Britain declared itself no longer part of the Roman empire and Carausius ,commander of the British Navy (classis Britannica), assumed power. The lands in the north off France , where he was born, joined this rebellion against Rome which lasted for 7 years until Constantius I attacked and defeated his armies and allies in Northern France and Batavia. Carausius was assassinated and Allectus took control of Britain until 296 when Constantius’s armies invaded from Boulogne and defeated him. Constantius restored order and the forts.
The map above show the extent of Roman coins in Scotland during this period. It can not be said that Romans lost these coins as they might have bene the result of trade or plundering. However each coin has a map of distribution around England and Walers and patterns can be seen – for example some coins are found in ports around Britain and so9me follow the routes of Roman roads into Scotland with many found at York’s (Eboracum) legionary fort which may indicate a marshaling of troops begore and advance into Scotland.