Footnote 26:

In July 1536, the emperor Charles V responded to a French invasion of Savoy by sending armies into Provence and along the French border with Flanders. The war was concluded in June 1538 without spreading to Paris, but as a Flemish native Vesalius was an enemy alien, and was forced to return to Louvain. See O’Malley 1964, p. 62.