The scenery follows Ingmar Berman's The 7th Seal. The first two panels as well as the chess game are optically copied from the movie.

The plot: Death appears to the knight (played by Max von Sydow) on the beach in order to reap him, and since he doesn't want to die, the knight persuades Death to play a game of chess with him, his life at stake. So far so good. In the movie, thus, the game endures throughout days, until Death finally wins.
It is my belief that Bergman allowed himself to interprete the facts in his own artistical way. In reality, it happened just the way you saw in the cartoon.

Oh, and yes, the musical symbol to the knight's whistling in the first panel is - historically correct - mensural notation.