Boswell was a major supporter of the Corsican Republic. Following the island's invasion by France in 1768, Boswell attempted to raise public awareness and rally support for the Corsicans. He sent arms and money to the Corsican fighters, who were ultimately defeated at the Battle of Ponte Novu in 1769. Boswell attended the masquerade held at the Shakespeare Jubilee in Stratford-upon-Avon in September 1769 dressed as a Corsican Chief.