Archaeologists have made a surprising discovery on the grounds of an Aberdeenshire castle.
Experts excavating at Fyvie Castle, near Turriff, expected to uncover a 400-year-old garden.
Instead they have discovered what they believe to be an 800-year-old defence system which they believe will help them learn more about the castle's history.
Archaeologist Alison Cameron said: "Initially when I was digging down one of these post holes I found a huge piece of 13th century pottery which I knew hadn't been moved around a lot, so I was thinking there was probably some structure underneath.
"It's potentially very significant. If it was possible to uncover more post holes and find out more about this structure it would be one of the only excavations which has taken place in Scotland of 13th century defences of a castle."
Shannon Fraser, of the National Trust for Scotland, said: "We don't know anything about medieval Fyvie at all. We know much more about later periods, but there is so much to learn. To come across 13th century pottery is just incredible."