Leone (or Leo) was the first magister militum (master of the soldiers), serving one year in 737. Otherwise, nothing is known about him.
The account of the election of the first three doges of Venice (Pauluccio, Marcello and Orso), from the “Istoria Veneticorum” by John the Deacon.
The complete list of the 120 Doges of Venice from Paoluccio Anafesto in 697 to Ludovico Manin in 1797