Kept: 9 October
9 October 1604.
People looked up and there was a star that had not been there before. Back then the sky was supposed to be fixed and perfect, never changing, so a new star was closer to a scandal than a wonder. It burned bright for about a year, then faded out of sight.
It turned out to be the last supernova in our own galaxy that anyone has seen with their own eyes. Four hundred years, and nobody has seen one since.
Things that have never happened before have a way of also being the last ones.