[6] As a teenager, Armistead suffered an accident with explosives that caused the loss of an eye and some fingers.
[8] He worked closely with another eminent Hispanist scholar, Joseph H. Silverman (1924–1989), and the musicologist Israel J. Katz (born 1930), with both of whom he developed an extensive body of work that focused primarily on the oral literature of the Sephardic communities of Morocco and the East.
He also worked closely with Hispanist Manuel da Costa Fontes on studies focusing especially on the oral traditions of Portugal and Brazil.
[5] In 2003 he published a six-volume collection of Portuguese traditional romances from the Azores Islands, and he was at work on subsequent volumes.
Armistead died on August 7, 2013, at 85 years old, in Davis, California, due to complications from surgery.
[9] His research fields that have had special impact include early poetry, medieval history, Hispanic dialectology, the Spanish epic and Romance, old and traditional.
[2][9] In addition, he performed pioneering studies on various genres of Hispanic oral tradition, such as the kharjas, riddles, the paremeología and folktales.