Please explain William the Conqueror's reasons for invading England in 1066?

The death of Edward the Confessor in early 1066 would prompt one of the most significant military campaigns in English history, the invasion of William of Conqueror. The reasons for William's invasion of England in 1066 are two-fold, firstly the reasons he used to legitimise his campaign and secondly the claim that he had to the English throne. There was a well-known thought in Europe at the time that the English church was rotten and not fit to serve the religious needs of the English people. As a result, William sent envoys to the pope to demonstrate the necessity of this divine mission to be the salvation of the souls of the English people. Such reasoning was a further way to persuade his Norman nobles to back his cause and therefore, contribute troops towards the invasion. Furthermore, the coronation of Harold had not been recognised by the pope, this gave further reasoning for William to claim that crowning him was illegal in the eyes of God. In giving religious reasonings for his invasion of England in 1066, William helped to legitimise the invasion, not just with his own nobles, but with the Catholic church.

While the religious reasonings behind William's invasion gave him reasoning for his invasion, there was a far more important reasoning that underlined the invasion. William did have a blood claim to the English throne, this was not simply conquest, this was claiming what he saw as rightfully his. William's great grandfather had been the maternal grandfather of Edward the confessor, giving him his blood claim to the English throne. While this was a weak blood claim, the claim of Harold Godwinson was equally weak, further strengthening William's arguments that he was not a legitimate king. In fact, the strongest blood claims to the throne came from the Scandinavian kings who would be defeated by Harold at Stamford Bridge. Despite this weak blood claim to the English throne, William was able to secure backing for his invasion because of the religious reasons that he found for the invasion, he had god on his side something other potential suitors for the English throne, such as Harold Hardrada, did not have.