Italian sculptor and medalist
Pompei Leoni was an Italian sculptor and medalist who was born in Milan in the early 1530s and died in Madrid in October 1608.
Biography.
Pompeo learned the art of sculpture and medal making in the house of his father, Leone Leoni, in Milan, called the , where he had set up a school.In addition to his Milanese customers, Pompeo, like his father, worked mainly for the Spanish monarchy. In particular, he collaborated with the sculptors Jacopo Nizzola, Bautista Comane, and Juan Bautista Monegro on the construction of the Escorial. Most of his sculptures are preserved in Spain.At his father's request, he amassed an important art collection. In his , published in 1584, Giovanni Paolo Lomazzo states that two mythological paintings by Correggio, and Danaë (now in the Kunsthistorisches Museum in Vienna and the Galleria Borghese in Rome, respectively), sent by Pompey from Lombardy, Spain, were preserved in the Leoni household in Milan. It is not known whether he received the works from the sovereign himself or whether he bought them from his favorite Antonio Perez after his disgrace in 1579.
Leonardo da Vinci's manuscripts.
In 1589, he came into possession of the notebooks, manuscripts, and drawings that Leonardo da Vinci had bequeathed to his pupil Francesco Melzi. When this latter died in 1570, his son Orazio Melzi distributed the manuscripts; he sold some and gave others to friends and collectors. Pompeo Leoni received some from Melzi and bought others. 
In 1630, Antonio Mazenta wrote about the distribution of Leonardo's manuscripts, accusing Pompeo Leoni of being one of the main culprits and of having altered their order. To distinguish between artistic and technical or scientific drawings, Leoni dismantled the original manuscripts and created two separate collections: the first, , grouped scientific and technical drawings, this is the Codex Atlanticus kept at the "Biblioteca Ambrosiana" in Milan. The second, , was intended to group botanical and anatomical drawings; it has been dismantled and the sheets can be found in several European collections, such as the "Codex Windsor" in the Royal Collection of Windsor Castle since the 17th century, and the Codex Madrid in the National Library of Spain.