A ruin believed to be one of the earliest stone-built castles in Scotland could be dated by a single piece of surviving timber used in its construction.
Castle of Old Wick stands on a narrow strip of land surrounded by cliffs on the Caithness coast.
Little is known of its origins, according to Historic Environment Scotland (HES).
HES is to have the fragment of oak removed from a stone joist socket on the castle's upper floor and then have it examined by experts in Edinburgh.
The public agency hopes dendrochronological analysis - or tree-ring dating - will be possible. If not, samples of the wood will be radiocarbon dated.
The fragment, which is decaying, will be conserved following analysis.
Some historians have suggested the castle, near Wick, was originally built in the 14th Century, before it was later developed.
Nicknamed The Old Man of Wick, the castle had a four-storey tower.