1. In 1787, Delaware was the first state to ratify the United States Constitution, earning it the nickname "The First State." December 11 is now celebrated as Delaware Day to commemorate this historic event.

2. The University of Delaware was founded on December 11, 1833, making it one of the oldest higher education institutions in the United States.

3. In 1936, Delaware became the last state to ratify the 21st Amendment, which repealed the nationwide prohibition on alcohol. The amendment was ratified on December 5, but didn't take effect until December 15.

4. December 11, 1862, marked the beginning of the Battle of Fredericksburg during the American Civil War. Many Delaware soldiers fought in this battle, which resulted in heavy losses for the Union army.

5. On December 11, 1934, the DuPont chemical company introduced the first successful synthetic rubber, which was called DuPrene. This breakthrough paved the way for the mass production of tires and other rubber products, and had a major impact on the automotive industry.