While Henry VII had won at the Battle of Bosworth, there was little guarantee that he would remain as king of England as there were many in the House of York who had a claim to the throne. Little known by many in the land before the battle at Bosworth, Henry clearly had a struggle on his hands to maintain his grip on the throne. That he was successful in this is down to a number of factors.
First his marriage to Elizabeth of York was a political marriage designed to unite both houses of York and Lancashire. That it developed into a strong marriage is not doubted – Elizabeth’s death had a major impact on Henry – but in its original intent it was to take the sting out of the friction that existed between both houses.
Second, Henry dated the time of his reign to the day before the Battle of Bosworth. Therefore, legally Richard and those that had supported him could be classed as traitors. As such anyone deemed guilty of treason could have all their property taken from them by an Act of Attainder. This was very convenient for a new king as he became the recipient of this land. It also meant that nobles would go out of their way to profess their loyalty to the king.
Third, Henry arranged for his coronation to be before the first sitting of Parliament after Bosworth. Henry was crowned on October 30th and Parliament met on November 7th. Therefore Henry could very publicly state that he did not need Parliament to declare him king as he was king before Parliament met.
Fourth, Henry applied to the Pope for a Papal Dispensation to marry Elizabeth – both were distant cousins. By the very nature of the difficulties of transport and travel then, there was bound to be a delay of some months between Henry, a devout Catholic, asking for a Papal Dispensation and him receiving such permission. Henry married Elizabeth on January 18th 1486. Therefore, he could argue that his crown did not owe anything to his marriage to Elizabeth. He was crowned in October 1485 and married some two-and-a-half months later.
His policies clearly worked as it was clear that by 1490, Henry was supreme in his power. There were problems such as the one that surrounded Lambert Simnel and Perkin Warbeck, but in general Henry was the supreme authority of the country by 1590.