Jan Długosz, also known as Joannes Longinus or Joannes Dlugossius (1415-1480) was a Polish historian (a chronicler ) and a secretary of Bishop Zbigniew Oleśnicki of Kraków.

He was a canon of Krakow educated at Jagiellonian University in Kraków. Casimir IV Jagiello sent him on diplomatic mission to the papal and the imperial court for important political business. He was involved in negotiations with the Teutonic Knights and king Casimir IV during the Thirteen Years' War (1454-66) and at the peace negotiations.

Longinus did not take the offered position to the archbishopric Prague, but shortly before his death he was elected archbishop of Lwów.

His works

• Liber beneficiorum ecclesiae Craceviensis ("Book of the Benefices of the Bishopric of Krakow")
• Historiae Polonicae libri xii originally appeared in 12 books between 1455 and 1480 but was not published in full until 1711-12 (2 vol.)