How did flying buttresses allow for larger stained-glass windows?

In Gothic architecture, the development of the flying buttress was a critical innovation that allowed for the creation of larger stained-glass windows by fundamentally changing how a building’s weight was supported.12

Previously, heavy masonry walls were required to bear the immense downward and outward pressure exerted by stone ceiling vaults. Because these walls had to remain thick and continuous to prevent collapse, they could only accommodate small windows.23

Gothic masons solved this by using ribbed vaults to concentrate the ceiling's weight onto specific points rather than along the entire wall. The flying buttress then transferred this outward thrust away from the walls to external, freestanding piers. By relieving the walls of their load-bearing function, masons were able to build thinner, lighter structures that could be opened up with expansive glazing. This structural shift transformed walls into a diaphanous stone skeleton, enabling the integration of the large, intricate stained-glass windows that define the Gothic style.2345