On July 27, 1377, the first example of quarantine occurred in Rugusa (now Dubroknik); the city council passed a law saying newcomers from plague areas must isolate for 30 days (later 40 days, quaranta in Italian). An excerpt from the article:
"After three disease-ridden decades, the republic’s Great Council decided on July 27, 1377 to establish a quarantine system. It was the first of its kind in the world. Lawbook Liber Viridis (‘Green Book’) marks its inauguration, under a decree stipulating Neither local nor foreign peoples coming from infected areas will be admitted to the city or surrounding land until they’ve undergone a month-long cleaning on the islands.
The new ruling sent travelers directly to the small, mostly barren islands of Bobara, Mrkan and Supetar and later Koločep, Lopud and Šipan, for 30 days. Occasionally, camps were built which could be assembled quickly and burned down just as fast if they became worn out or the plague passed. Often, however, those sent to the islands had nowhere to hide from rain, wind, cold or summer heat.
The Great Council added to the quarantine law in 1397. A new isolation length of 40 days was authorized. The initial, 30-day quarantine was dubbed trentine, but with the new 40-day regulation came a new name: quarantena. Punishments for disobeying were also defined and ranged from fines and jail time to draconic public shaming."