Gen. Douglas MacArthur, supreme commander during the Allied Occupation of Japan, once considered attempting to convert Emperor Showa to Christianity, a diary of the U.S. secretary of the Navy shows.

In his diary, James Forrestal wrote that during his meeting with MacArthur in Tokyo on July 10, 1946, the general said he had "given some consideration" to persuading the Emperor to convert but thought it would need a "good deal of reflection and consideration before it could be carried out."

Kyodo News obtained a copy of the diary, which was found at the library of Princeton University, Forrestal's alma mater in New Jersey. The author later became the first U.S. secretary of defense, a post created in 1947.