According to former Nintendo of America localization manager Leslie Swan, the production of the North American manual for Super Mario Bros. was outsourced to an unspecified American advertising agency. In the process, they were the ones who coined Princess Peach's original western name, Princess Toadstool. During the development of Super Mario 64, series creator Shigeru Miyamoto relayed his confusion about this change to Swan and his preference for the original name. To compromise, Swan came up with the idea of Princess Toadstool using Peach as an informal nickname, and at the beginning of the latter game, Peach formally signs her invitation to Mario as "Princess Toadstool" before writing "Peach" on top of it to appear more casual.