[1][2] Jan Długosz is best known for his Annals or Chronicles of the Famous Kingdom of Poland  [pl; ru] (Annales seu cronici incliti regni Poloniae) in 12 volumes and originally written in Latin, covering events throughout southeastern and western Europe, from 965 to 1480, the year he died.

In 1450, Długosz was sent by Queen Sophia of Halshany and King Casimir to conduct peace negotiations between John Hunyadi and the Bohemian noble Jan Jiskra of Brandýs, and after six days' of talks convinced them to sign a truce.

In 1461 a Polish delegation which included Długosz met with emissaries of George of Podebrady in Bytom, Silesia.

Długosz declined the offer of the Archbishopric of Prague, but shortly before his death was nominated Archbishop of Lwów.

At some point in his life Długosz loosely translated Wigand of Marburg's Chronica nova Prutenica from Middle High German into Latin, however with many mistakes and mixup of names and places.