While these unfortunate controversies were weakening and disheartening the Catholics the penal laws were enforced with great severity. One martyr suffered in 1607, three in 1608, five in 1610, two in 1616, and five in 1618. Great numbers of priests were confined in prison or transported abroad. Laymen were ruined by imprisonment, and especially by the high fines required by the king to meet his own expenses. According to his own statement he received from the fines of Popish recusants a net income of £36,000 a year. Parliament and the Protestant party generally were anxious about the marriage of Prince Charles, the heir to the throne, and of the princess Elizabeth his sister. If they were married into Protestant families the religious difficulty, it was thought, might disappear; but, if, on the contrary, they were united to the royal houses of France or Spain the old battle might be renewed. Hence the marriage of Elizabeth to the Elector Frederick of the Palatinate, one of the foremost champions of Protestantism in Germany, gave great satisfaction at the time, though later on it led to serious trouble between the king and Parliament, when Elizabeth's husband was driven from his kingdom during the Thirty Years' War. Regardless of the wishes of his Parliament the king was anxious to procure for Prince Charles the hand of the Infanta Maria, second daughter of Philip III. of Spain. To prepare the way for such a step both in Spain and at Rome, where it might be necessary to sue for a dispensation, something must be done to render less odious the working of the penal laws. Once news began to leak out of the intended marriage with Spain and of the possibility of toleration for Catholics Parliament petitioned (1620) the king to break off friendly relations with Spain, to throw himself into the war in Germany on the side of his son-in-law, and to enforce strictly all the laws against recusants. But the king refused to accept the advice of his Parliament or to allow it to interfere in what, he considered, were his own private affairs. The marriage arrangements were pushed forward, and at the same time care was taken to inform the magistrates and judges that the laws against Catholics should be interpreted leniently. In a few weeks, it is said that about four thousand prisoners were set at liberty. The articles of marriage were arranged satisfactorily (1623), due provision being made for the religious freedom of the Infanta, and a guarantee being given that the religious persecution should cease, but for various reasons the marriage never took place. Parliament promised the king to provide the funds necessary for war if only he would end the negotiations for a Spanish alliance, and this time James much against his will followed the advice of his Parliament (1624). A new petition was presented for the strict enforcement of the penal laws against priests and recusants, to which petition the king was obliged to yield.