<nowiki>Juan I de Sajonia-Lauenburgo; Jean Ier; Иоганн I; Johann I.; John I, Duke of Saxony; John I dari Sachsen-Lauenburg; Йохан I; Johan 1. af Sachsen-Lauenburg; Janez I., vojvoda Saške; ヨハン1世 (ザクセン＝ラウエンブルク公); Ιωάννης Α΄ της Σαξονίας; John I, Duke of Saxony; Johan I av Sachsen-Lauenburg; Jan I; Іоганн I; Johan I van Saksen-Lauenburg; جون الاول دوق ساكسونيا; Giovanni I di Sassonia-Lauenburg; Joan I de Saxònia; Іаган I; John I, Duke of Saxony; John I, Duke of Saxony; Jan I. Saský; 約翰一世; vojvoda Saške-Lauenburga (1249–1285); Herzog von Sachsen-Lauenburg; герцог Саксен-Лауэнбурга; German duke; duc de Saxe-Lauenbourg; saský vévoda; duque alemán; Juan I de Sajonia; Johann I av Sachsen-Lauenburg; Helene av Sachsen-Lauenburg; Johan 01 av Sachsen-Lauenburg; Johann I dari Sachsen; Johan I van Saksen</nowiki>
English: Duke John I of Saxony (1249 – 30 July 1285, Wittenberg upon Elbe) was the elder son of Duke Albert I of Saxony and his third wife Helen of Brunswick and Lunenburg, a daughter of Otto the Child. John and his younger brother Albert II jointly ruled the Duchy of Saxony after the death of their father Albert I in 1260. Since in 1296 John's three sons and their uncle Albert II partitioned Saxony in Saxe-Lauenburg (joint duchy by John's sons) and Saxe-Wittenberg (Albert II), John I is sometimes referred to, though anachronistically, as John I of Saxe-Lauenburg.
