1. On March 5, 1770, the Boston Massacre occurred, which played a role in shaping Illinois history. The event, in which British soldiers killed five colonists in Boston, further inflamed tensions between the American colonies and Britain, ultimately leading to the American Revolution and the eventual founding of Illinois as a state in 1818.

2. On March 5, 1849, the Illinois Supreme Court ruled in the case of Jones v. Van Zandt that a contract for the sale of slaves was void, even though slavery was still legal in Illinois at the time. The ruling was a significant step toward the state's eventual abolition of slavery, which officially occurred with the adoption of the 13th Amendment to the U.S. Constitution in 1865.

3. March 5, 1868, saw the adoption of the Illinois Constitution of 1868, which established the state's government as it still exists today. The new constitution replaced the previous one, which had been in effect since 1848, and created a stronger executive branch and a more efficient judicial system.

4. March 5, 1969, was the date of the first Chicano Moratorium in East Los Angeles, which protested the disproportionately high number of Chicano casualties in the Vietnam War. Many Illinoisans participated in the event or supported the Chicano movement in other ways, helping to foster greater recognition and empowerment for Latinos in the state and the country as a whole.

5. In recent years, March 5 has been celebrated in Illinois as Multiple Sclerosis Awareness Day, with events and activities taking place around the state to raise awareness and support for the millions of people affected by the disease worldwide. This ongoing effort helps to promote health and wellness for all Illinoisans and to inspire positive change in the lives of those impacted by MS.