I don't know of any major attacks on the wall, but from what I understand it was quite high and had fortifications and barracks built into it that were spaced at regular intervals. It was an engineering marvel and would have required a military marvel to break through it while it was capable of being defended. Rome eventually had to withdraw its troops from Britannia (probably late-4th/early-5th century) and we know that the place was culturally abandoned. I imagine that it was like a Mad Max type of world where a shell of a past civilization existed and only stragglers were left.BTW I add to the notion that the wall was painted, though I don't recall where I heard this (could have been on this forum for all I know ;D ).
I too, have never heard or read of any major attacks against the wall. From my understanding the attacks against the wall were more like the death of a thousand cuts. The totality of the effects of many small attacks gradually wore down the Roman's ability to defend against them. Something else to consider is that the Scots were not unified then and indeed would not unify in any meaningful way until well into the Middle Ages. They were a tribal and clan dominated society much like the Arabs of the Middle East today. Their loyalty was to clan and tribe and only last to nation if such a concept can even be said to have had any meaning in the 2nd and 3rd centuries.
I know the wall was built across the shortest distance from coast to coast.You might be thinking of the shorter Antonine Wall.
Yes I was, thanks. In 138 AD there is an offensive assault on tribal lands, Antonius is then pushed back 17 years later by the Brigantes, the same happens at least once more before the Romans leave Briton. I see you are correct Skiguy et. al. about the wall being a boundary marker. Some say its Hadrian's own personality reflected in the monumental scar to the landscape. However, Hadrian said the wall will be built because the Britons were not conquered. Didn't Rome generally assimilate occupied territory, leave a small force behind and then move on? And why so many thousands of soldiers at the wall? Just wondering what you all think. These points are raised by Andrew and Robin Birley.