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At the time Christians were forbidden from charging interest, so Jews ended up being the only ones who could lend money. These laws likely were only enforced against Jews. There ended up being a lot of economic jealousy towards them that eventually led to their expulsion from the country in 1492.
The Jews in medieval Catalonia were an important part of the banking system, but not the only ones. Non Jews, specially from Lingua di Si countries, and also members of the Court, engaged in loans and taules de canvi.
Edit: capitalisation of ethnonyms.
I'm just gonna say if that was the end point I'd have already sold off all my property to avoid it.