1. In 1638, the Swedish colony of New Sweden was founded in what is now Delaware. This marked the first permanent European settlement in the state, and the colony would go on to play an important role in the region's early history.

2. On April 22, 1778, British forces under General William Howe sailed up the Delaware River and attacked the town of Upper Ferry (now Morrisville, Pennsylvania) as part of their campaign to capture Philadelphia during the Revolutionary War. The attack was ultimately unsuccessful, and the British were forced to withdraw.

3. The Delaware State Fairgrounds, located in Harrington, Delaware, opened on April 22, 1920. The fairgrounds have since become a popular venue for events and concerts, and is home to the annual Delaware State Fair.

4. On April 22, 1970, millions of Americans participated in the first Earth Day, a national day of environmental action organized to raise awareness about environmental issues and advocate for environmental protection. Delaware played an important role in the movement, with events and rallies taking place throughout the state.

5. On April 22, 1994, the Delaware Art Museum announced the acquisition of Pierre-Auguste Renoir's painting "Portrait of Mademoiselle Legrand". The painting, which was completed in 1872, is now part of the museum's permanent collection, which includes works by artists such as Edward Hopper, John Sloan, and Howard Pyle.