He also had several concubines, and a second wife (of nearly as illustrious a group of royal forebears as himself).
So, why bring him up? Well, he turns into an ancestor of Henry VIII, Philip of Spain, Isabella AND Ferdinand of Spain, most of the Hapsburgs who were capable of walking and chewing chiclis at the same time, and, lo and behold, he actually had Christopher Columbus as an employee at one time.
To say the French and Spanish crowns were closely related is to say the least. By the late 1500s Rene had become an ancestor to the next half dozen Swedish kings (all Protestant).
The "family", as its called, is still pretty tightly knitted (as families go), but back then it owned everything. Didn't matter who found the gold or brought it to Europe, it ended up in the same place every single time.
One of the places it tended to not go was Espagna. Instead, it went to the creditors.
Now you might not think Philippines gold was worth all that, but it was, and it traveled through the backdoor lest Spanish ships be boarded by such nice people as Dutch, French, Portuguese, Arab, Thai, Hindu, Malay and African pirates. There were lots of them around in those days.
Now, about banking, Venice started out on its own with the First Doge some time in the 7th century AD.
Those old boys invented double entry book-keeping. They also figured out how to monetize debt.
I think your reference to "banking" is to a more "modern banking" situation with internationally transferable "letters of credit". Spain had had access to that through its affiliation with the Islamic Caliphate starting in the 8th century AD right up to the 16th century. Of course even the Babylonians had banking and bankers thousands of years ago.