In 1792, several regiments of the French Irish Brigade were sent to the colony of Saint-Domingue in the Caribbean as part of efforts to suppress a slave rebellion there.
Irish Brigade troops in Saint-Dominigue subsequently switched sides and assisted a British invasion of the colony which began in 1793; Pitt authorised payments to these defectors.
As well as Saint-Domingue, other units of the Catholic Irish Brigade were established in 1795 and posted to safer but more tedious and unglamorous garrison duties in places such as Nova Scotia.
While the Brigade only lasted for 4 years, with a maximum strength of 4,500 men, it demonstrated Pitt's understanding that many Irish Catholics would support his war against the French republican state.
Losses from disease, difficulties in recruitment, competition from other formations and the outbreak of the Irish Rebellion of 1798 all ended Pitt's experiment.