Many of the early concepts and theorems of graph theory came about quite indirectly, often from recreational mathematics, through puzzles, or games or problems that, as were seen later, could be phrased in terms of graphs. The very first of these was a problem called the Ko¨nigsberg Bridge Problem, which was not only solved by one of the most famous mathematicians of all time but whose solution is considered the origin of graph theory and would lead to an important class of graphs.