(3 syl.); Italian Lazzaro, plu. Lazzaroni. The mob. Originally applied to all those people of Naples who lived in the streets, not having any habitation of their own. So called from the hospital of St. Lazarns, which served as a refuge for the destitute of that city. Every year they elected a chief, called the Capo Lazzaro. Masaniello, in 1647, with these vagabonds accomplished the revolution of Naples. In 1798 Michele Sforza, at the head of the Lazzaroni, successfully resisted Etienne Championnet, the French general.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894