In the years 1734/35, the Kingdom of Naples fell into the hands of the Spanish Bourbons, who, according to the Treaty of Vienna, had to establish a second sonship in the Mezzogiorno. King Charles, who had come to appreciate the Swiss military contingents in the Spanish army during the conquest of Southern Italy, subsequently entrusted two Swiss officers with the task of forming new Swiss regiments for the Neapolitan crown. So far, there have been hardly any significant findings published regarding the Swiss-Neapolitan military services of the 18th century. Due to this research gap, there is a pressing need for modern, socially-historically inspired foundational research. The study focuses on the four Swiss regiments in Neapolitan military service between 1734 (the time of their establishment) and 1789 (their dissolution). Through source-based critical analyses, the investigation aims to address and discuss a topic area that has so far been neglected by scientific historiography, providing new insights into the organization and structure of the Swiss troops in Naples.