Croati a cavallo (Cavalleria Croati) was a cavalry unit, one of the leading elite overseas Venetian forces in the early modern period, and majority of its complement comprised of officers and soldiers originating from Croatian areas, from Istria to the Gulf of Kotor. Due to archival material deposited in Venice (State Archive in Venice, archival collection Inquisitori sopra l’amministrazione de’ pubblici ruoli) and Zadar (State Archive in Zadar, collection of Records of General Provisor), it is possible to determine and chronologically follow military agency and career of a number of distinguished Venetian officers of Croatian origin. In this article the focus is placed on Simon Nassi, a member of one of the oldest noble families with an important role in the social life of Dalmatia and Zadar. The article follows his military career until the last decades of the seventeenth century, when he participated in the War of Morea (1684-1699), first as a lieutenant and then as a captain. In the year of 1708, Nassi was promoted to the rank of lieutenant colonel because of his accomplishments and war merits and until 1713 he acted as the commander of one of Croatian cavalry units belonging to the regiment of Nicholas Divnić, a nobleman of Šibenik. Then, Nassi was appointed colonel and acquired his own cavalry unit with history of which deals also the major part of this article. The composition of the regiment of Simon Nassi is analysed in a greater detail, especially officers and military personnel acting within the framework of his own regiment in the period of 1714-1718, when the last Venetian-Ottoman war took place. In the Appendix, the transcript of the list containing military personnel of Nassi’s regiment from 1711, 1714 and 1718 are published.