MAY DAY MASSACRE
King Arthur let send for all the children born on May-day, begotten of lords and born of ladies; for Merlin told King Arthur that he that should destroy him should be born on May-day, wherefore he sent for them all, upon pain of death; and so there were found many lords’ sons, and all were sent unto the king, and so was Mordred sent by King Lot’s wife, and all were put in a ship to the sea, and some were four weeks old, and some less. And so by fortune the ship drave unto a castle, and was all to-riven, and destroyed the most part, save that Mordred was cast up, and a good man found him, and nourished him till he was fourteen year old, and then he brought him to the court.
— Le Morte d’Arthur, Sir Thomas Malory
The story of the massacre of the innocents is undeniably a part of the Arthurian tradition. It is not a pretty story, nor does it accord with the general characterization of King Arthur as an ideal king, a man dedicated to peace who cares for the needs of his people.
King Arthur ordered a slaughter of innocents, and of his own son Mordred. Malory does not attempt to justify Arthur’s order, but he does provide a reason for his having given it. Merlin told him that the man who would destroy him “and all the londe” would be born on May Day. The motive for Arthur’s act could have been a desire to preserve his own life and thus protect his kingdom. The safety of a kingdom depends on the leadership of a strong, living king. It can also be observed that Malory’s Arthur chose a method of killing that at least partially displaces the responsibility for the consequences of his act. It is by “fortune” — and no man controls fortune — that the ship carrying the babies is wrecked on the shore. The method is chosen also avoids the blame attached to an act that a man performs with his own hands.
— King Arthur and the Massacre of the May Day Babies, Marie Nelson
Max Irons as King Arthur | [Alas, I took artistic liberty with the ages of the children for editing purposes]
Arthurian Legends 