The first Italian edition of Machiavelli’s Complete Works (Tutte le Opera) was released in 1550 or MDL in Roman numerals. But the volume here is not that edition, but rather a seventeenth-century "false imprint." In the course of the 1550s, Machiavelli's (1469-1527) works were put on the Pope's Index, or list of forbidden books (Galileo's Dialogi also made the list). This imprint—published between 1628 and 1660—used the earlier date to avoid censorship.
The four Geneva printings are known as the "Testina Editions," because they carry on their title pages the "little head" of Machiavelli, seen here.