Reluctantly, George IV Assents to Catholic Emancipation

Parliament passed the Roman Catholic Relief Act of 1829 on March 24, but King George IV waited until April 13 to give his Royal Assent. Like his father, King George III, the former Prince Regent, was concerned that his Royal Assent was a violation of his Coronation Oath to support and defend the Church of England.

While he was Prince of Wales, however, George had been married to a Catholic, Maria Fitzherbert. He had to leave her and make his dynastic marriage to Caroline of Brunswick, whom he would later also repudiate. As this website explains, Fitzherbert was twice a widow when she and George met:

Born Maria Smythe, she was the eldest daughter of Mary Ann and Walter Smythe, the son of a knight. Maria was raised as a Roman Catholic, and received an adequate education at a convent in France. When she was 18, Maria was married for the first time, to Edward Weld, a wealthy landowner. The marriage lasted barely three months, before Edward was thrown of his horse and died from the injuries sustained by the fall. His sudden death meant that he didn’t even have time to update his will to include Maria in it, and upon his death all his lands passed to his younger brother, leaving Maria widowed and penniless. Now in a desperate situation, Maria married for a second time, to Thomas Fitzherbert. Within three years, he too was dead – killed in the anti-Catholic Gordon Riots of 1780. Fortunately for Maria, the provisions of his will left her with a town house in Park Street, and an annual income of £1,000.

He begged her to become his mistress, but she (like Anne Boleyn?) held out to become his wife. Their marriage was illegal, since it violated both the 1701 Act of Settlement and the 1772 Royal Marriage Act. It was kept a secret and as king George denied it every occurred, but Maria had the documentation and used that fact often to defend her reputation and the truth. She and the Prince lived as husband and wife in Brighton for about ten years, then his mounting debts led him to renounce her and marry his cousin. After he and Caroline of Brunswick separated and she travelled in Europe, George III finally died after a reign of 60 years (interrupted by madness), she returned to claim her role as queen. From the same blog:

When King George III died in 1820, George IV became King. Technically, this made Caroline Queen of the United Kingdom, and in June 1820, she arrived on the English shore, demanding to be recognised as Queen. She gathered a large number of supporters, who launched riots in London in her favour, much to the displeasure of the new King George. On his advice, Parliament tried to persuade Caroline to leave England forever, offering her an increased annuity of £50,000, which she reluctantly accepted.

But Caroline was determined that she at least be crowned Queen, and on the day of King George’s coronation in 1821, she arrived at Westminster Abbey. “The Queen…Open,” she shouted, demanding to be let in. “I am the Queen of England.” But all doors were slammed in Caroline’s face that day, and she stormed away in humiliation, without being allowed to enter the Abbey. That evening, she complained that she was feeling unwell, and three weeks later, she died, aged 53. In her will, she expressed her desire to be buried in her native Brunswick, in a tomb bearing the inscription “Here lies Caroline, the Injured Queen of England”.

It's rather confusing that a man who violated his marriage oaths (twice) would be so concerned about his coronation oath! A bigamist with scruples!

Perhaps the greatest influence on him and his reluctance to assent to Catholic Emancipation was George's younger brother, Ernest Augustus, the Duke of Cumberland and later King of Hanover. As the Wikipedia biography of the Duke explains his efforts to thwart the passage and approval of Catholic Emancipation, he failed:

In 1828, Ernest was staying with the King at Windsor Castle when severe disturbances broke out in Ireland among Catholics. The Duke was an ardent supporter of the Protestant cause in Ireland and returned to Berlin in August, believing that the Government, led by the Duke of Wellington, would deal firmly with the Irish.[54] In January 1829, the Wellington Government announced that it would introduce a Catholic emancipation bill to conciliate the Irish. Disregarding a request from Wellington that he remain abroad, Ernest returned to London and was one of the leading opponents to the Catholic Relief Act 1829, influencing King George IV against the bill.[55] Within days of his arrival, the King instructed the officers of his Household to vote against the bill. Hearing of this, Wellington told the King that he must resign as Prime Minister unless the King could assure him of complete support. The King initially accepted Wellington's resignation and Ernest attempted to put together a government united against Catholic emancipation. Though such a government would have had considerable support in the House of Lords, it would have had little support in the Commons and Ernest abandoned his attempt. The King recalled Wellington. The bill passed the Lords and became law.[56]

He had also gathered signatures from Protestants in Ireland protesting against the passage of Catholic Emancipation and presented that petition to Parliament.

If you read through just a few of the speeches given by the Duke of Wellington in the House of Lords (which included the Anglican Bishops) to encourage the reading and the passage of this bill, you can certainly see how contentious this issue was in Parliament--the crux of the issue being that since Catholic attorney Daniel O'Connell had won a seat in Parliament, the King's Government in England feared an uprising in Ireland if he was not allowed to take his seat, since he was Catholic--for fear that Emancipation, removing all the penal laws, would in fact encourage the growth and spread of Popery and weaken the Church of England. Robert Peel worked on passing the Emancipation Bill in the House of Commons. Since both Wellington and Peel were Tories and were previously opposed to Catholic Emancipation, they were regarded as traitors.

Of course, this being a matter of politics, someone had to lose in the deal. The poorer landowners were disenfranchised as only a male with property worth 10 pounds per year could vote (the minimum had been 2 pounds per year) and the Irish still had to pay taxes to support the Church of Ireland (which led to the Tithe Wars). Most of the burden for electing O'Connell and forcing the government to acknowledge the danger of not letting him take his seat had been borne by the peasants of Ireland. The middle class Catholics of England truly benefited from the removal of restrictions on their livelihood and political representation, although they still could not attend at Oxford or Cambridge because an oath to uphold the Thirty-Nine Articles of the Church of England was a graduation requirement.

The act also sought to limit the growth of monasteries and the presence of Jesuits in England--but at last, Catholics were relatively free to practice their faith and be full citizens of their country.