The article covers that: >And then, of course, there’s the matter of the new century. As some may remember from the whole Y2K hullaballoo, centuries (and mille

The article covers that: >And then, of course, there’s the matter of the new century. As some may remember from the whole Y2K hullaballoo, centuries (and millennia) only end when the year ending in zero is over, not when it starts. So, just like the 21st century and the third millennium started on January 1, 2001, the 20th century began on January 1, 1901, not 1900. (Not that this chronological truth got in the way of popular opinion.)