The school's situation changed in 1900 with the appointment of Percy Shaw Jeffrey as headmaster. He took over a school with 29 boarders and barely any staff, but his reforms rapidly turned the school around. He introduced day boys and established a preparatory school, a cadet corps, an orchestra, a bugle band, school entertainments and theatrical performances. He was a national pioneer of the teaching of modern European languages through phonetics, employing language teachers from France and Germany and setting up arrangements for foreign study during holidays. He also founded the Old Colcestrian Society to reconnect former pupils with the school.