John was born about 1635 probably at Dromana, the only son of
Gerald FitzGerald and his wife
Mabel Digby. His father was esquire of Dromana and styled Lord of the Decies. His family was a cadet branch of the FitzGerald of Desmond, an Irish
Old English family. The Dromana branch started when Gerald FitzGerald, the second son of
James FitzGerald, 6th Earl of Desmond (died 1462) was given Dromana as appanage. His mother was the second daughter of
Sir Robert Digby and his wife
Lettice Digby, 1st Baroness Offaly. Her family was English and Protestant. == Irish Wars ==