To turn a blind eye

To turn a blind eye - deliberately overlook

Admiral Hortaio Nelson, better known as Lord Nelson, was blinded in one eye early in his Royal Navy career. In 1801, during the seige of Copenhagen Lord Nelson, second in command of the English fleet, was ordered by his superior Admiral Sir Hyde Parker to withdraw forces by flag signals. When made aware of such signals, Nelson deliberately put the telescope to his blind eye and said he could see no such signal. Thus, he ignored the order as if he had not seen it and ordered his forces to continue the attack. Luckily for him, English won the day.

Supposedly he remarked later that he had a blind eye and sometimes had a right to use it! :)

Even if Nelson did not exactly use the phrase "turn a blind eye" or invent it, the phrase is based on this event in his life.

Sources: Wikipedia, http://www.phrases.org.uk/

Image: LIFE Images

Quarantine

Quarantine - A condition of enforced isolation.

The word comes from a Venetian custom in the Middle Ages when ships arriving from the reported plague-stricken countries were obliged to spend 40 days (Italian "quaranta" or "forty" comes from the Latin "quadraginta," also meaning 40) at the port, in isolation, before being allowed to unload its cargo and crew. Venice, in those days, was the chief European port of entry and Europe had experienced many epiemics of plague. Forty days was supposed to be long enough to kill the infection for goods (and people) by exposure to air and sunlight.
The current usage of the word is not limited to 40 days but "any period" of isolation.

Trivia: Quarantine first appeared as a legal term in 1609, as the period of 40 days in which a widow could remain in her dead husband's house before creditors could seize it.

Sources: answers.com, etymonline.com, Wikipedia