1688. William III of the Netherlands had a Jewish friend.
Alright, let's give a quick overview for those not up on their European history. King James II of England (also King James VII of Scotland, let's not deal with that confusion here) was a Catholic. He had no male heirs. His two daughters, Mary and Anne, were Protestant.
Now, in 1688, with James in the ripe old age of 55, his wife gave birth to a boy. Some say that he was not the royal couple's real child, since the queen seemed to be barren for more than a decade. In any case, a new heir to the throne of England is born. A Catholic heir.
Obviously, England's Protestants don't like that. So they ask the Dutch for help. Stadtholder William III is married to Mary, who would be denied any chance of the English throne by the new heir, so he thinks it's a good idea to invade. One problem: he needs money.
So William goes to Francis Lopes Suasso, one of the richest men in the Netherlands. (And, yes, a Jew. His family were marranos who came to Holland and then reverted to Judaism.) Suasso lends William two million guilders, and also helps arrange the transport of some Swedish troops that will help the Dutch.
The army lands in England, and James II is deposed in what is called the Glorious (or Bloodless) Revolution. William and Mary become joint monarchs of England and Scotland, completely changing the course of history. Suasso is repaid.
Good thing William had a rich Jewish friend, right?
P.S. Nice wig.