Résumé : In a chronological list of Historical dates, the author shows his interest in The Order of Saint John (OSJ). He attempts to draw a concise History to the order, from its beginnings in Jerulamen to its first Exile from the holy land. The OSJ: "Ecumenical" Christians before their time; sovereigns in Government without land; Republicans ruled by a Prince whose very election as leader made him Prince; Chivalrous in their behaviour, benefactors to the sick and wounded, in body or in soul, christian or not; real-estate promoters, innovators in medical resarch, trainers of the European navies. The long list of their humanitarian activities makes them a founding force of today's Public Health' systems.