Who is Thomas Cranmer and Thomas Cromwell from The Six Wives of Henry VIII and what is their importance?

Cranmer and Cromwell both advised Henry in the later years of his reign. Cranmer, a scholar, discovered an academic reason for Henry's divorce. A archbishop, he later become a protestant, though privately. He was also integral in assisting Henry with the end of his marriage to Katherine Howard and encouraged his relationship with Katherine Parr.