Two important manuscripts commissioned by Ludovico il Moro for his son Massimiliano Sforza, the so-called Grammatica del Donato and the Liber Iesus (Milano, Archivio Storico Civico e Biblioteca Trivulziana, Triv. 2167 and 2163), were written by Giovanni Battista Lorenzi, a scribe operating in Milan between the end of the 15th and the beginning of the 16th century. Other manuscripts are attributed here to Lorenzi for the first time, shedding new light on his versatile activities. He copied a number of manuscripts for the Arluno and the Tolentino families, mostly encomiastic works, medical and historical treatises composed by members of these patrician families (Milano, Biblioteca Ambrosiana, D 34 bis inf., O 133 sup., S.P. II 25, S.P. II 254; Milano, Biblioteca Nazionale Braidense, Morbio 21). Lorenzi also wrote or transcribed notarial deeds, including a legal document concerning the inheritance of Vitaliano Borromeo, here newly attributed to his hand (Milano, Archivio Storico Civico e Biblioteca
Trivulziana, Fondo Morando Litta Visconti Arese, cart. 7 / 1. c. III).