Hamilton was not able to continue the Greyfriars saga immediately, as the Amalgamated Press claimed ownership to all the characters except Billy Bunter who actually appeared in a Sparshott story in 1946. However, by 1947 they had relented, and Hamilton was then able to obtain a contract from publishers Charles Skilton for a series of stories to be issued in hardback form. The first of these, "Billy Bunter of Greyfriars School", was published in September 1947. It began a series that continued for the rest of Hamilton's life. In the 1950s the initial novels were reprinted by Cassells, who took over publication of the series.