At the age of two William's hands and feet became nearly paralyzed, either from polio, or from a doctor administering a dose of calomel (mercurous chloride).

[2] William Trego first received public attention when he exhibited a painting titled The Charge of Custer at Winchester in 1879 at the Michigan State Fair.

His depiction of George Armstrong Custer's charge at the Third Battle of Winchester was described by the Cleveland Press as "one of the best historical paintings of the kind that has ever been produced by an American artist.

In 1886, he lost the case, with the Pennsylvania Supreme Court ruling the jury was well within their rights under the contract of the exhibit to award prizes as they saw fit.

Except for trips abroad, Trego would live in North Wales for the rest of his life, working in a studio behind his house.

But in a sad and very public event on board ship, the "handsome French girl" (as reported in the newspapers of the time)[11] switched her affections to fellow Académie Julian student[12] James R.

Trego's increasing financial problems during this time made him take on students including Walter Emerson Baum and his wife, Flora.

These would become so widely published after his death that writer Edwin Augustus Peeples commented: In 1976, Trego's The March to Valley Forge had become such an iconic image of that event that it was reproduced as a souvenir postage sheet issued by the United States Postal Service as part of the observance of the United States Bicentennial.