In 1321 his patron, Guido Novello da Polenta, sent him on an embassy to Venice, in which he was unsuccessful.

The sea way being blocked, he had to return by land, and he was struck by the malaria which caused his death by fever on the 14th of September in that year, 1321.

This reference to long exile leads to an inference that the First Treatise was written much later than 1300.
But, again, there is a passage in the third chapter of the Fourth Treatise (on page 171 of this volume) that points to an earlier date.
Frederick of Suabia is named as the Emperor who held, As far as he could see, Descent of wealth, and generous ways, To make Nobility.
Dante calls him "the last Emperor of the Romans," and adds, "I say last with respect to the present time, notwithstanding that Rudolf, and Adolphus, and Albert were elected after his death and from his descendants." This last of the Romans was that famous Frederick II., who died in 1250, and of whom Dante said in his Treatise on the Language of the People: "The illustrious heroes, Frederick Caesar and his son Manfredi, followed after elegance and scorned what was mean; so that all the best compositions of the time came out of their Court.
Thus, because their royal throne was in Sicily, all the poems of our predecessors in the Vulgar Tongue were called Sicilian." Rudolf I.of Hapsburg, founder of the Imperial House of Austria, was elected Emperor in 1273, after a time of confusion and nominal rule.

He died in 1291, and, instead of his son Albert, Adolphus of Nassau was next elected Emperor.

But in June 1298 Albert obtained election; Adolphus was deposed, and was soon afterwards killed in battle with his rival.
Albert was murdered on the 6th of May, 1308, and, after an interregnum of seven months, he was succeeded by Henry VII.