1. Louisiana became a state: On October 15, 1812, Louisiana officially became the 18th state in the United States. The state had previously been a territory under French and Spanish control before being purchased by the United States in 1803 as part of the Louisiana Purchase.

2. Huey P. Long was assassinated: On October 15, 1935, Louisiana Governor Huey P. Long was assassinated at the age of 42. Long was a controversial figure and had intended to challenge President Franklin D. Roosevelt in the 1936 election.

3. First jazz recording: On October 15, 1923, the first jazz recording was made by the Original Dixieland Jazz Band in New Orleans. The recording, "Livery Stable Blues," was a hit and helped to popularize jazz music throughout the country.

4. Louisiana Purchase treaty ratified: On October 15, 1803, the Senate ratified the Louisiana Purchase treaty, which had been signed by President Thomas Jefferson in April of that year. The treaty transferred control of the Louisiana Territory from France to the United States.

5. First African American state senator elected: On October 15, 1868, P.B.S. Pinchback was elected to the Louisiana State Senate, becoming the first African American to serve in that position. Pinchback, who had previously served as lieutenant governor, filled a vacancy caused by the expulsion of a white senator who had openly supported the Confederacy.