Who is Thomas Fitz Thomas from Falls the Shadow and what is their importance?

Thomas Fitz Thomas was the mayor of London when Simon waged war against King Henry III. A commoner, he fully supported Simon's side of the war. Fitz Thomas rallied the people of London behind Simon, giving him strong support and offering him soldiers from among the London common people. After Simon's death, Thomas Fitz Thomas was arrested and jailed for many years as revenge for the support he gave Simon.