John I, Duke of Lorraine

John I (February 1346 – 23 September 1390) was the Duke of Lorraine from 1346 to his death. As an infant of six months, he succeeded his father, Rudolph, who was killed in the Battle of Crécy. His mother was Mary, daughter of Guy I of Blois.

During his long minority, the regency was in the hands of his mother and Eberhard III of Württemberg. In December 1353, John did homage for the duchy to Charles IV, Holy Roman Emperor, who made him lieutenant-general of the Empire in the Moselle country. In 1354, John II of France granted him a dispensation to allow him to govern the duchy despite not yet being of age.

John participated in the Drang nach Osten and its related crusades at the sides of the Teutonic Knights against Lithuania in 1356 and again in 1365.

On 19 September 1356, he aided John II of France in the Battle of Poitiers, as his father had at Crécy, and the French cavalry were mowed down by English longbowmen as before.He survived, however, unlike his father, to fight again, although he was taken prisoner by the English. He later fought on the side of the Dauphin Charles in putting down the Parisian rebellion of Étienne Marcel.He attended Charles' coronation on 19 May 1364 in Rheims, strengthening the ties to France which had steadily been building in Lorraine for the past century.

He entered the War of the Breton Succession, as had his father, to aid his uncle Charles of Blois against John of Montfort.At the Battle of Auray on 29 September 1364 with John as undisputed duke and Charles dead on the field, John was taken prisoner.

He continued to aid Charles V and Charles VI to reconquer the provinces lost by the Treaty of Brétigny, but in his latter years, he distanced himself from the French court.Partly this was due to the free companies ravaging his lands and in part the royal officials who tried to litigate the relationship between John (an Imperial vassal) and his vassals.In the end, he entered into rapprochement with Philip II, Duke of Burgundy. Nonetheless, he died at Paris on 22 September 1390, defending himself against a charge by the people of Neufchâteau of abuse of power.

John married Sophie of Württemberg (1343–1369), daughter of Eberhard II, Count of Württemberg and Elizabeth von Henneberg-Schleusingen, in 1361.They had issue:

• Charles II, Duke of Lorraine (1364–1431)
• Frederick of Lorraine, Count of Vaudémont (1369–1415)
• Isabelle of Lorraine (d.1423), married Enguerrand VII, Lord of Coucy.

John later married Marguerite de Chini (d. 1372), who is interred at Orval Abbey.

• Bogdan, Henry (2007). La Lorraine des Ducs (in French). Perrin.