Why did Edward III depend on Parliament to fund his wars?

Edward III’s dependence on Parliament for war funding was rooted in the necessity of securing "supply" to sustain his military campaigns, particularly during the Hundred Years' War. Because the costs of these wars were immense—leaving the king significantly indebted by 1339—he required consistent financial grants from the Commons and other estates to maintain his efforts.1

This relationship was defined by a constitutional precedent: the principle that "common dangers should be met by remedies agreed upon in common". As the king’s need for revenue grew, Parliament leveraged this necessity to exert influence over royal governance. For instance, in 1341, Parliament attempted to impose restraints on the king, such as requiring royal officials to be appointed and accounts to be audited within Parliament.21

Ultimately, Edward III found that complying with the requests of the Commons made it easier to obtain the necessary grants. By 1352, he formally agreed that no one would be required to provide soldiers for the war without common consent in Parliament, further cementing the legislative body's role in authorizing the resources required for his military ambitions.1