During the American Revolution, the pro-England/pro-King people were called
Tories (and the term still persists today in England for conservatives). When
did this term come into use? What is it derived from?

Hi,

The spelling for the term is actually "Tory" (the plural is "Tories"). It came 
into use around 1689, when that political party was founded. It's derived from 
the Irish word "toraidhe", which means "pursuer" or "robber".

Here are some links about the etymology of that word.

Dictionary.com
http://www.dictionary.com/cgi-bin/dict.pl?term=tory&r=67
To·ry (tôr, tr)
n. pl. To·ries 

A member of a British political party, founded in 1689, that was the opposition 
party to the Whigs and has been known as the Conservative Party since about 
1832. 
A member of a Conservative Party, as in Canada. 
An American who, during the period of the American Revolution, favored the 
British side. Also called Loyalist. 
often tory A supporter of traditional political and social institutions against 
the forces of democratization or reform; a political conservative. 


--------------------------------------------------------------------------------
[Irish Gaelic tóraidhe, robber, from Old Irish tóir, pursuit. See ret- in Indo-
European Roots.]

Trailblazerworld.com
http://www.trailblazer.ie/generation3/regionssystem/commonpages/writearoundirela
nd/leinster/louthcontent.html
""Tory" was a word used to describe renegade gunslingers and highway bandits in 
17th and 18th century Ireland, taking its name from the Irish word for 
outlaw, "toraidhe". Tory Island in Donegal was originally a stronghold of the 
legendary Fomorians, Cyclopean one-eyed pirates who raided Ireland's western 
coast in the days of the Little People. The name was adopted into the English 
language by the Whigs in 1679 to describe those in Charles II's court, led by 
Thomas Danby, opposed to the succession of his Catholic brother James, Duke of 
York (for whom New York is named) who, as James II, got his ass got whipped at 
the Battle of the Boyne by King Billy 12 years later. Whether O Doimin was a 
robber or not, I do not know, but he scarpered anyway, teaching at a few local 
schools - including Kilkerly, 3 miles west of Dundalk - before fetching up as a 
schoolmaster in Forkhill, County Armagh, where he died a year after the 
abortive Fenian Rising in 1768."

Guardian Unlimited
http://politics.guardian.co.uk/conservatives/story/0,9061,620577,00.html
"The term 'Tory' is a corruption of the 16th century Irish word 'toraidhe', 
meaning 'pursuer.' Originally a term of abuse of for Catholic outlaws who 
terrorized English soldiers, it became the nickname for the political faction 
who backed Charles and his brother James II in the 1688."

Note that if you search Google for "tory", you will see this sentence in the 
blue bar at the top: "Searched the web for tory", where the word 'tory' is a 
link to the dictionary definition and etymology.

More useful Google searches:

tory OR tories toraidhe
tory OR tories etymology

Thanks! The answer is very complete and helpful. My only comment is that I'd be
concerned if this answer were being used by a child for a school report. The
sentence in the answer that I found surprising was:

"The name was adopted into the English language by the Whigs in 1679 to describe
those in Charles II's court, led by 
Thomas Danby, opposed to the succession of his Catholic brother James, Duke of 
York (for whom New York is named) who, as James II, got his ass got whipped at 
the Battle of the Boyne by King Billy 12 years later."

I know that you're just quoting from another source. It was just strange to see
this, ahem, "colloquial" language in what otherwise reads like a scholarly
exposition.