When William Tolbert replaced the long-serving William Tubman as President in 1971, he retired more than 400 aging soldiers. Sawyer comments that "retired soldiers were replaced by young recruits from urban areas, many of whom were then poorly trained at the Tubman Military Academy. This development dramatically changed the character of the military in Liberia." (Samuel Doe was among this group.) Amos Sawyer also comments that "recruitment of such individuals for the military was part of Tolbert's efforts to replace aging, illiterate soldiers with younger, literate men who were capable of absorbing technical and professional training."