Final answer:
Duke Ellington and Count Basie were the two most famous big band leaders in history.
Step-by-step explanation:
The two most famous big band leaders were Duke Ellington and Count Basie. Both were influential jazz musicians and bandleaders during the early to mid-20th century. Duke Ellington's band, the Duke Ellington Orchestra, was known for its sophisticated arrangements and innovative compositions, while Count Basie's Kansas City-style band was known for its tight rhythm section and swinging sound.
Ellington and Basie achieved great success and popularity, attracting diverse audiences and leaving a lasting impact on the big band genre. Their music continues to be celebrated and studied today.