Wonderful science fiction book on an alien ship crashing by remote German village on the eve of its devastation by the Black Death. The village priest, an intellectual who had to hide in the area after taking part in peasants' rebellion, understood that the aliens are thinking creatures in distress. Thus he managed to convince the villagers and the lord of the manor to assist them. He also managed to convince the aliens to accept his ideas of charity. Later, while some of the aliens left, others remained to assist during the Black Death.
Another part of the story is a contemporary couple - a physicist and a historian. The historian researches the village in question and the odd stories told about it in the area. The notion that the aliens were in the area was raised when his physicist partner accidentally noted the similarity between a medieval sketch and her own machinery.
Overall, a slow going story about the excitement of doing research and about the humanity of there who managed to overcome their fears of strangers and to collaborate in survival.