Saint John of God, originally João Cidade Duarte, was motivated by the deplorable conditions in mental institutions of his time, particularly the cruel treatment methods, which prompted him to dedicate his life to the care of the ill. He envisioned establishing a hospital where he could serve the poor, stating, "May God grant me time to found a hospital where I could accept these poor and serve them as I wish." He founded the first hospital in Granada, Spain, which innovatively included separate rooms for the elderly, abandoned individuals, and various sick people, making this approach revolutionary for that era. Thus, he earned the title "founder of modern hospitals."

After a transformative religious experience, John of God devoted himself wholeheartedly to the care of patients, founding several hospitals to provide them with necessary support. His dedication to the sick and his founding of the Brothers Hospital order enabled the establishment of two hospitals in Zagreb and Zadar, which continue his mission of service. The legacy of Saint John of God lives on through these institutions and his extensive influence on hospital care, demonstrating the profound impact one individual can have on healthcare in society.