Franklin and Penelope Shields worked the land in Texas with their seven sons. P.T. Barnum’s agents heard about the sons, who were called "giants," and went to investigate. In the late 1870s, Barnum hired the four of the men to tour in his Barnum & Bailey sideshow as "The Texas Giants."
We know everything in Texas is bigger. That includes the exaggerations. The Shields Brothers were plenty tall: Shade Shields was 6 feet 8 inches tall, Guss Shields was 6 feet 9, Frank Shields was 6 feet 10.5, and Jack Shields was 6 feet 11. However, Barnum billed them all as being over seven feet tall. Family members later said they wore lifts in their shoes during showtime. The brothers toured for over ten years. When the others quit touring, Shade continued with his wife Annie O'Brien (who was 6’ 7") as the "Tallest Married Couple" until the turn of the century.
There were originally nine sons, one of whom died as a teenager, the other died in the Civil War. Frank Shields’ grandson, Marcus Ross Freiberger, was 6’ 10” tall and played on the US Olympic basketball team when they won the 1952 gold medal in Helsinki. -via reddit