Thomas Stanley was head of an extremely powerful family and a clever and devious politician. Richard III granted him the very influential position of Constable of England and when Henry Tudor's father, Edmund, died Thomas Stanley married his widow, Lady Margaret Beaufort. By this act he became the future king's stepfather.

Lord Stanley, however, was not very trustworthy. He and his family connections had the reputation for changing allegiances between Yorkist and Lancastrian supporters (depending on which House was likely to be on the winning side). Surprisingly, not only did they manage to get away with this, but each time they did they ended up even more powerful.

Richard was aware of the Stanley's nature and, to ensure their loyalty against the coming threat, he imprisoned Stanley's son, Lord Strange as a hostage. A measure of Lord Stanley is that when told his son would be executed if he wouldn't support Richard in his fight against Henry, Stanley replied that he wasn't too worried as he had other sons! Lord Stanley was taking a bold gamble not to openly support one side or the other. He was waiting to see who was more likely to win, fight for them and be rewarded for his efforts. This was to prove decisive at Bosworth.