A unanimity rule paralyzed the Aragonese Cortes until its 1592 replacement.

Evidence

For the Spanish kings, there was no more favorable situation for suppressing the Aragonese Cortes than this very “freedom”: until 1592, the Cortes could make no decision once even a single member of the four estates disagreed. This so paralyzed action that a less cumbersome substitute was required forthwith. — Georg Simmel, The Sociology of Georg Simmel, 6151