The High Crusade

In 1345, Sir Roger Baron de Tourneville is raising an army in Lincolnshire to join King Edward III in the war against France. Then a huge silver ship comes down from the sky and lands in a pasture beside the village of Ansby.

The ship belongs to the Wersgorix, a species that scouts and takes over planets by routine. They judge Earth suitable from orbit and begin their standard conquest. They have not reckoned on free Englishmen, who fight back against the landing party.

Only one alien survives, and Sir Roger sees a use for him. He means to have the creature fly the ship to France to help the King, then on to the Holy Land to defeat the infidel.

The alien pilot has other plans. He steers the craft to his home planet, expecting these barbarians to have no choice but to surrender. The book turns on whether medieval knights, far from England and badly outmatched, can win on ground that belongs to their enemy. It is science fiction played as medieval adventure, with a comic edge.