The 2nd Battatlion, The 73rd Highlanders were raised in 1778 and sailed from England in 1779 on route to Gibraltar, pausing to take part in the Battle Cape St. Vincent (1780) as part of a marine force. The Battalion landed in Gibraltar, where they remained throughout the Siege of Gibraltar 1780-83 repelling many French and Spanish attacks.
For their efforts during the siege they were granted the insignia of the Castle and Key on the Colours.
The 2/73rd earned high praises for their efforts during the Siege of Gibraltar with Stewart of Garth stated that within the 2/73rd “not a man was punished. or deserted to the enemy“.