Although established in 1891, it was not until the First World War that the Swiss company Angelus really came into its own, making excellent in-house and quite innovative complicated mechanisms. Panerai chose the Angelus 8 day movement for some of their military watches in 1939, proving their mechanisms to be robust and versatile.

But it was the introduction of one of the first series chronograph watches with the appearance of a calendar on the dial that really propelled Angelus into the limelight in 1943 with their introduction of the 'Chronodate'. A triple calendar, later named 'Chronodato,' it utilized the calibre SF217, a superior in-house mechanism.

The date is indicated by a red hand pointing to a chapter ring on the dial, and the ‘jump day and month windows’ at 6 and 12 o’clock respectively.