It’s unclear when exactly unicorns became significant in Scottish culture, but they are seen in the Royal Coat of Arms at Rothesay Castle, which was created sometime before the 15th century and is probably the earliest depiction in Scotland.
In Celtic mythology, the unicorn was a symbol of power, strength and grace. It is seen as a wild and free-roaming beast; beautiful and difficult to tame. You may have spotted the unicorn often has chains wrapped about its legs and body; this is to symbolise how dangerous and difficult it is to capture.
Bearing this in mind, it makes sense why Scotland chose a unicorn to symbolise the nation’s struggle for independence from England.
In 1603 King James VI of Scotland, succeeded Queen Elizabeth 1st of England to become King James the 1st of England. This was known as the Union of the Crowns. This union of Scotland and England required a new coat of arms. The design of a lion and unicorn holding up a shield is still used to this day.