Quarantine just means forty. It's a shortening of the Italian phrase quarantina giorni, which meant (and means) forty days. This was because of a policy implemented by the Most Serene Republic of Venice to protect itself from the plague. Any ship that was suspected of possibly having the plague on board would have to wait offshore for forty days before docking. The idea was that any hidden cases would present themselves.
Presumably, if the plague was on board then everybody was in a lot of trouble. I suppose that they just sailed back to where they had come from. An alternative was that suspect people could stay on a small island to see just how plaguey they were. The island was known as a lazaretto.
In Venice the Lazaretto Vecchio still exists. It's a small island just off the Lido. I'm not sure whether you can visit it, or whether you'd want to. Archaeologists have found 1,500 skeletons there so far, and they're rather hopeful that there are some more.
The word lazaretto as a place for the plagued comes from Luke's Gospel, chapter 16:
There was a certain rich man, which was clothed in purple and fine linen, and fared sumptuously every day: And there was a certain beggar named Lazarus, which was laid at his gate, full of sores, And desiring to be fed with the crumbs which fell from the rich man's table: moreover the dogs came and licked his sores.
It turns out that Lazarus goes to Heaven and the rich man goes to Hell. History does not relate what happened to the dog. Or, to put it another way, God knows what happened to the dog.
Anyway, you should have been able to work out that God would help Lazarus in the end, as Lazarus comes from the Hebrew El'azar, which means He whom God has helped. It's rather odd really, as Lazarus became, in many European languages a synonym for leper or plague-victim, which seems unhelpful even by God's standards.
Oddly enough, when quarantine first appeared in the English language, it had nothing to do with plague. It was the place where Jesus fasted for forty days and forty nights. It first pops up in a travel guide for pilgrims to the Holy Land written in 1470:
Beyond is a wilderness of quarantine, where Christ with fasting his body did pine.
Although the author, William Wey had got to Jerusalem via Venice, so he might have picked up the word there.
Today we remember Christ fasting and pining by giving stuff up for Lent. Pancake day is today and Lent begins tomorrow. I shall abstain from rhubarb and women, for the sake of continuity; but an old word for Lent was - you have guessed it, dear reader - quarantine. Forty days of fasting.
Then quarantine started to mean the period of forty days that a widow was allowed to remain living in her dead husband's house. And finally, in the seventeenth century we started using it for its proper purpose of plague. However, the word had already become rather imprecise. The second citation in the OED is from Samuel Pepys' diary in 1663, where he suddenly veers off into etymology:
The plague, it seems, grows more and more at Amsterdam; and we are going upon making of all ships coming from thence and Hambrough, or any other infected places, to perform their Quarantine (for thirty days as Sir Rd. Browne expressed it in the order of the Council, contrary to the import of the word, though in the general acceptation it signifies now the thing, not the time spent in doing it) in Holehaven, a thing never done by us before.
But the original quarantine, first enforced in 1377, was Venetian. And so, by such divigations and tergiversations, quarantine has finally come home.
Enjoy your pancakes while you can. Quarantine begins tomorrow.
The Inky Fool arrives at his Venetian hotel