I gave a talk today on Margaret Beaufort, looking in particular at her early life and the role that she played in bringing her son, Henry VII, to the throne. For much of his life Henry VII was a penniless exile, living in Brittany. The fact that he was able to become a credible contender for the crown owes much to his mother's persistence in attempting to engineer his return to England.
Margaret Beaufort is one of the most fascinating characters from the late medieval/early Tudor period. You can read more about her in my biography of her!