It has been chiefly during great European conflicts that the English Parliament has obtained its power and importance.

Properly speaking, it owes its formation to such a conflict. When in the year 1265 Queen Eleanor, in alliance with the powers predominant in the West, the Pope and the King of France, was arming a mercenary force in Flanders for an invasion of England, Simon de Montfort, in order to obtain a broader basis for resistance, introduced the lower nobility and the deputies of the towns into the council of the spiritual and temporal magnates in England.

Parliament was formed while England stood on the defensive; it subsequently acquired its most important powers while the undertakings of different kings against Scotland and against France were being carried out. On the chief question in dispute during the fourteenth and fifteenth centuries, that relating to the succession to the French throne, the English Parliament gave the support of popular co-operation to its kings who claimed a right to that throne. There was no parallel to the personal position which kings like Edward III and Henry V, thus supported, attained in the world; but their government assumed at the same time a parliamentary character.

In the sixteenth century ecclesiastical questions came everywhere into the foreground. In England the crown and the Parliament made common cause in order to establish the ecclesiastical independence of the country,—under forms however which departed as little as possible from those previously accepted.