I looked up the Battle of Belleau Wood...The date(s) were June 1-29...
Also I believe the Normandy Invasion is a little more historically relevant than Prop 13...
The decisive action at Belleau Wood—the fight at Hill 142—took place on June 6. But it is true that it took several more weeks to clear the Germans out of the woods.
Prop. 13 may somewhat less significant than the Normandy invasion or the Battle of Belleau Wood, but it was a major event in our recent history. In December, 1976, I was one of about 15 or so people to attend a meeting in a guest room at a hotel across the street from the University of Southern California, where Howard Jarvis pitched his plan get a proposition to limit property taxes onto the ballot. Hardly anyone save a few conservative activists knew at the time who Jarvis was. A year and a half later, he was on the cover of Time Magazine, and I’ll never forget the election night party on June 6, 1978.