Saint John of God was born in Montemor O Novo in 1495. When eight years old, John was placed into a family in Oropesa in Spain and later became a shepherd. Twice he enlisted in the Spanish army against the French and later the Turks. After being discharged from the army, he ultimately made his way in 1538 to Granada, having made a living as a bookseller in Gibraltar.
His life was dramatically changed after hearing a sermon preached by Saint John d’Avila in Granada. For a while he was mentally disturbed and he was admitted to the Royal Hospital for the insane. As a result of this experience, John took up the call to serve the poor and the sick because of the mistreatment of the patients in the Royal Hospital he had witnessed and experienced, and was determined to change the practices of the day. He was offered a shelter in Granada (the porch of Casa Venegas) where he took his first patients. It was through this venture that John came to gather the support of many people and particularly the encouragement of the Bishop of Granada who gave him a distinctive form of clothing, and sowed the seeds of the Hospitaller Order of Saint John of God.
Others followed in his work, and his way of life continues after his death in 1550.
In 1630, John was declared Blessed by Pope Urban VIII and was later declared a saint and canonised in 1690 by Pope Alexander VIII. In 1886, he was proclaimed patron of hospitals and the sick, and in 1930 he was further proclaimed patron of nurses and their associations by Pope Pius XI.