I have read variously that the Templars were the first international bankers. If not, they were among the earliest. Whatever their methods and codes, they appear to have worked. Their mistake was loaning to royalty, a mistake that perhaps Nicholas Flammel had some experience with.
The ancient Greeks and Romans also had a sophisticated banking system, and with a legal framework that was so well-conceived and durable that it became the foundation for Europe’s commercial and banking law. The Templars made the fundamental mistake of forgetting in their pride that, even if utterly in the right, you risk your very existence if you tell a monarch no. It is far better to say, yes, of course, Sire — and then raise all sorts of delays, conditions, and practical objections.