1. On May 9, 1761, the first Masonic Lodge in Massachusetts, St. Andrew's Lodge in Boston, was chartered. Freemasonry has played a significant role in the history of Massachusetts, with many prominent figures being members of the organization.

2. In 1786, a convention was held in Springfield, Massachusetts, to discuss the ongoing economic crisis in the state. This convention ultimately led to the calling of a constitutional convention and the drafting of the Massachusetts Constitution, which is still in use today.

3. On May 9, 1893, the New England Telephone and Telegraph Company was incorporated in Boston. Telephone technology had a profound impact on Massachusetts and the world, creating new forms of communication and transforming the way people interacted with each other.

4. In 1936, the Massachusetts Statehouse in Boston was officially designated as a National Historic Landmark. The Statehouse has played a central role in Massachusetts politics since it was first built in 1798.

5. On May 9, 1959, the Boston Celtics won their first NBA championship, defeating the Minneapolis Lakers in Game 7 of the finals. The Celtics have gone on to become one of the most successful franchises in NBA history, winning a total of 17 championships as of 2021.