1.  William S. Bryan & Robert Rose.  1876.  A History of the Pioneer Families of Missouri.  Bryan, Brand & Co., St. Louis, MO:

p. 258	FIPPS.--William FIPPS, Jr., son of William FIPPS and Rebecca KENDRICK, of Washington Co., Va., married the widow of John KING, whose maiden name was Barbara A. STROUP...
p. 274	KING.—Isaac King, of Germany, settled in Wythe county, Va., and married Barbara Stroup (late Mrs. Fipps, of Montgomery county, Mo.), by whom he had one son, John P.  The latter settled in Montgomery county in 1835 and married Susan Steph-
p. 275	enson; a granddaughter of James Heller, of revolutionary fame, and who was at the battle of Bunker Hill.

2.  Messages posted to the KING Surname Board (online at Ancestry.com).  An informative post there by Robert Stroupe indicates Barbara had an illegitimate child and accused our subject of being the father.