William was the son of William Armistead Jr. and Judith King. He was born about 1720 or possibly later as his parents married in 1719.
Marriage
William married Elizabeth Moseley (b. 1715-1741), daughter of Captain William Moseley, III.
Children
Dates of birth of children appear to be guesses.
Hannah, b. ca. 1736; married John Bayley (b. 1730)[1]
William, b. ca. 1738
Anthony. b. ca. 1740
Moseley, b. ca. 1742
Death and Interment
William is purported to have passed before Feb 1754,
https://www.wikitree.com/wiki/Armistead-1080#Biography