These partying men from 1876 might have wondered in their drunken stuper that somebody in the future will get the leap year calculation wrong. Well, of course they were having such a gay time they were hoping for more leap years. Maybe one of them passed that thought onto their heirs at Microsoft. I have a personal connection to the 1900 leap year (or should I say lack thereof). My great aunt was born on February 29, 1896. She was famous in our family as she didn’t have a chance to celebrate her birthday until she was 8 years old. There was not a leap day in 1900. Since Julius Caesar started leap days every four years to keep the calendar synched with nature we found he was a little off. 1500 years later the Gregorian calendar aimed to fix the crude adjustment by adding some more rules. Anyway, the outcome is that 1900, or any century year for that matter that, is not evenly divisible by 400 is not a leap year. Microsoft didn’t investigate it well enough and the calculation inherent in Excel is wrong. They mistakenly show 1900 as a leap year so changing history unbeknowingly. Apparently, they feel it is too much effort to correct it so future generations can debate about the reality or the virtual reality of Microsoft. Luckily, at the moment, WIkipedia sets the record straight with a well defined definition of the calculation. Will the 21st Century Shakespeare say, “Beware the Ides of Microsoft?” More on that the next post.