Shit I didn't know until today. The word quarantine comes from the Venetian word quarantena, meaning 40. It referred to how long ships had to be isolated at Dubrovnik (Ragusa) during the Black Death. Earlier, the isolation period had been specified as 30 days, and was referred to as "trentino."
The Ragusa part is new to me. Is that what Croatia was formerly known as?
That's what Dubrovnik was formerly known as. It's a long, complicated story, much of which is speculative. It was originally an Ostragothic town, and likely called Dubron in Gaulish. Tangentially, "dubron" is the Celtic word upon which the name Dover is based.
Anyway, when the Ostragothic kingdom fell, the Byzantines took over. They "officially" named it "Rhaousin," which is latinized as Ragusa. But you know how people are when they live in a place that gets "officially" named. The Ostragothic name stuck around, and when the Slavs started moving in in waves in the 7th century, they associated the old name Dubron with their word for "oakwood," which is "dubrovnik." The names Ragusa and Dubrovnik competed for centuries, until 1808, when the name Dubrovnik was officially adopted.
