Back in the 40s, musical films were so ubiquitous, they needed their own category to honor the underscore! The category has gone through a lot of name and qualification changes since, from Adaptation and/or Treatment Score (like Marvin Hamlisch doing Scott Joplin riffs for The Sting) to Original Song Score (like Yentl) to its current designation, the unused Original Musical.
In 1946, it was simple: Best Music, Scoring of a Musical Picture was the category name. And these were the nominees:
