According to the endnotes, Crispin: The Cross of Lead was Avi's fiftieth published book. I've read a couple of other books by Avi and enjoyed them. This one, however, deserved the Newbery award, I think. And it was set in the Middle Ages, my favorite historical period to read about.
Asta's son, a thirteen year old peasant boy, without a name, accused of a crime he didn't commit, meets Bear, a huge and possibly mad, man, who becomes Asta's son's master and mentor. The boy is given the name of Crispin and a cross of lead that belonged to his mother by the priest in his home village, but he must flee the village and the enemies who are determined to capture and even kill him. So, Crispin: The Cross of Lead is a journey/quest story. Crispin must escape his pursuers and find out who he really is and what his purpose in life is to be.
The story takes place in fourteenth century England, and at least one of the minor characters in the book is a historical figure. John Ball was "an English Lollard priest who took a prominent part in the Peasants' Revolt of 1381." Not a great deal is known of Mr. Ball's antecedents, but he was "hanged, drawn and quartered in the presence of Richard II on July 15, 1381." Luckily for the reader, Crispin ends before this untimely and violent end of John Ball the priest. The book does paint a rather dark picture of life in medieval England, probably a rather accurate picture. I want to re-read another Newbery award book, Adam of the Road by Elizabeth Janet Gray (1943) to compare the two. Adam of the Road is set about a century earlier than Crispin in England, and as I remember it, Adam of the Road depicts a much brighter, more idyllic, picture of medieval life than Crispin does. Another good book for comparison would be The Door in the Wall by Marguerite deAngeli, another Newbery book. All three books would be good read aloud books for a classroom or homeschool study of the Middle Ages.
There's a sequel to Crispin: The Cross of Lead called Crispin: At the Edge of the World, also by Avi.