Albert Cashier served in the army as a man, lived his life as man and was buried at 71 with full military honors in 1915, as a man. But beneath the uniform in which he fought and was buried, he was biologically a woman, one of the many cross-dressers and gender defiers who have served in the U.S. military since the earliest days of its history, according to historians.

President Trump’s proclamation by tweet Wednesday that he was banning transgender people from serving in the military in “any capacity” is the latest twist in a thoroughly modern controversy. Trump’s declaration would overturn a policy only recently put in place by the Obama White House as the armed forces continue to grapple with modern issues of gender identity and sexual orientation. But behind the 21st century contretemps is a history that predates the musket.

“They wouldn’t know what in the world you meant by the world transgender, but there have women serving in men’s dress in armies since the beginning of wars,” said Elizabeth Leonard, a professor of history at Colby College. “It’s a story that we keep losing sight of.”