The Marine Band is entirely separate from its sister military band, the United States Marine Drum and Bugle Corps ("The Commandant's Own") and the 10 active duty Marine Corps field bands.
The Marine Band has been uniquely known as "The President's Own" since 1801 due to the historic connection to the President of the United States. The relationship between the Marine Band and the White House began on New Year's Day 1801, when President John Adams invited the band to perform at the Executive Mansion.
Later that year, Thomas Jefferson initiated the tradition of Marine Band performances by requesting that it perform at his inauguration. The Marine Band has played at every United States presidential inauguration since. President Thomas Jefferson gave the title "The President's Own" in 1801. This terminology emulated a long-established British usage, where various military units were designated as "King's Own" or "Queen's Own".
Today, the Marine Band performs in approximately 500 events every year including state funerals, state arrival ceremonies, state dinners, parades, concerts, and other social events. The Marine Band also travels across the country each October and November during its fall concert tour, a tradition that began in 1891 under its most famous director, composer John Philip Sousa.
According to wikipedia