Having eighteen ships and 800 soldiers provided by Henry VIII of England, Lennox succeeded in taking the Castles of Dunoon and Rothesay.

[12] In 1646 occurred the Dunoon massacre in which the Campbells slaughtered men, women, children, and infants of Clan Lamont.

[13] After the restoration of the episcopacy under Charles II, Dunoon became the residence of the bishops of Argyll for a time.

[14] The castle was destroyed during the Earl of Argyll's rebellion against James VII and II in 1685.

During World War I and II, military fortifications were established at Dunoon Castle for the defense of the River Clyde and the shipbuilding industry.