His father, who was born in Boston, was a physician who spent nearly the last fifty years of his life practicing in Washington.
[1][2] His paternal grandparents were Abigail (née May) May and Col. John May, who participated in the Boston Tea Party and became a prominent soldier in the American Revolutionary War.
[4] In September 1861 May was arrested without charges or recourse to habeas corpus on suspicion of treason and held in Fort Lafayette.
In March 1862 he introduced a bill requiring the federal government to either indict by grand jury or release all other "political prisoners" held indefinitely without recourse to habeas.
[9] In 1862, Henry May and Ohio Congressman Clement Vallandigham, an anti-war Democrat, led an investigation into telegraphic censorship of the press instituted by Lincoln's Secretary of State William H. Seward in certain cities.