Why Easter has a different date each year

Today in 1861 – American Civil War: The war begins with Confederate forces firing on Fort Sumter, in the harbor of Charleston, South Carolina.

Today in 1955 – The polio vaccine developed by Dr. Jonas Salk is declared safe and effective. How effective? Do you ever HEAR of polio any more? We lived with the fear of it when I was a kid.

Today in 1999 – United States President Bill Clinton is cited for contempt of court for giving “intentionally false statements” in a civil lawsuit; he is later fined and disbarred.