This week we’re taking a look at how people literally left their mark on history through graffiti.

Although we tend to think of graffiti as relatively modern phenomenon, the impulse to scratch, scrawl and draw on walls and buildings is nothing new — and there are plenty of examples at English Heritage sites. Joining us to reveal more are English Heritage’s senior curator Kevin Booth and Emma Bryning, who is studying our historic graffiti as part of her PHD at the University of York.

To discover the story of the remarkable graffiti left by conscientious objectors at Richmond Castle, go to www.english-heritage.org.uk/visit/places/richmond-castle/richmond-graffiti.