Quote Originally Posted by Zarky
Pretty much like that, expects that they had chapter houses all over Christian-Europe, and it was dangerous to move around with bag full of money, so they gave the money to Templar chapter house and received somekind of note and code or something, so they could cash the same amount from any other chapter house.
They were actually first worldwide bank in world or something...
The Templars started acting as bankers as a way of facilitating crusading efforts (one of their constant problems was persuading enough fighters to go to the Holy Land outside of the major crusades).

The idea was that a knight could go to his local chapter house, pay in some cash and then be able to draw from all chapter houses on route, either in the local currency or (far more likely) in kind (i.e., replacement horses, bed and board and so on). This was intended to make it easier to go on crusade and did help increase the number of military personnel who made it to Outremer.

This got corrupted over time and the Templars did become moneylenders in a more conventional sense.

Of course, they were never in the same league as the Jews had always been or as the northern Italians who got in on the game around the same time.

As for the Templars being the first worldwide bank, this ignores:

a) them not operating worldwide
b) their banking efforts being predated by several centuries by the efforts of many, many others (most notably the Jews, who are known to have been engaged in banking throughout the Hellenic world in pre-Roman times).