If the Anglo-Scottish union formed a major political issue during the first years of James I's reign, the question of how to respond to the European crisis acquired an equally dominant position in English politics towards the end of the reign. England had been entangled in the European crisis from the very beginning, ever since James's son-in-law Frederick had accepted the Bohemian crown offered to him after the Bohemians had renounced their allegiance to the Archduke Ferdinand, heir-apparent to the Holy Roman emperor. Although James had tried to persuade Frederick to turn down the offer and had consequently not acknowledged Frederick as king of Bohemia, the situation changed dramatically when the Catholique League not merely crushed the Bohemian army, but also occupied Frederick's hereditary Palatinate on the Rhine with Spanish troops. Frederick and Elizabeth were popular in England and their popularity grew further with the Spanish intervention. The English parliament, which met in 1621, earnestly pleaded with the king to restore the Palatinate to Frederick by force. James also condemned the Spanish intervention since it upset the status quo, but he preferred a peaceful settlement. He assumed that Spain controlled catholic Europe and placed his hopes on the negotiations about a marriage between Prince Charles and the Spanish Infanta which had been going on since 1614. These negotiations looked like foundering in 1618 over the issue of toleration for English catholics, but the pursuit of a negotiated settlement of the international crisis revived hopes of a Spanish match.