Why did Edward I borrow money from Italian bankers?

Edward I borrowed extensively from Italian bankers primarily to finance his costly military campaigns in Wales, France, and Scotland, as well as to manage heavy debts he had incurred while on crusade.1234

To secure these loans, Edward used his customs revenues—specifically duties on wool, woolfells, and hides—as collateral. Throughout his reign, he relied on different banking firms to manage these financial needs:1

• The Riccardi: Based in Lucca, they served as the king's primary bankers during the first part of his reign but were driven into bankruptcy in 1294 due to the immense costs of the king's wars.25
• The Frescobaldi: A Florentine family that succeeded the Riccardi. They provided significant loans to Edward I and his successor, Edward II, and were granted extensive control over English revenues, including the mint and customs, in return for their financial support.25

These loans were essential for mobilizing resources on an unprecedented scale, allowing Edward to maintain paid forces and build major fortifications, such as the castles in North Wales.3