After 1900, the financial and official records from Henry's reign began to become accessible to historians, including the pipe rolls, court records, correspondence and records of administration of the royal forests. Thomas Frederick Tout made extensive use of these new sources in the 1920s, and post-war historians brought a particular focus on the finances of Henry's government, highlighting his fiscal difficulties. This wave of research culminated in Sir Maurice Powicke's two major biographical works on Henry, published in 1948 and 1953, which formed the established history of the King for the next three decades.