The South Wing of the Old Executive Office Building was the first wing to be completed. The Department of State occupied this building from 1874 until 1947.
The State Department Library was completed in 1876. The architect was Alfred B. Mullet and William McPherson of Boston was the decorator. The room was used as the State Department's library until 1947 when the State Department vacated the building. The Library was a popular tour stop in the late 19th century. Washington guide books of the late 1800s have accounts of the elegance and beauty of the gold and pearl room. On display were the Declaration of Independence, the Constitution, the Presidential Seal, and presidential papers. Washington's sword and Franklin's crabtree walking stick were also on display.
The room was restored in 1983. Restoration of the room included a paint analysis by the National Park Service that revealed the original colors. The coved ceiling is the only original stencilling found in the building never painted over, and was cleaned to restore its beauty. The room is of cast iron and plaster construction; the floor is of Minton tile. Minton tile is an English encaustic tile, which holds its color within the body of the tile. The book shelves are cast iron and were originally covered in sheepskin. The roof restoration project undertaken in the early 1990s allowed for natural light to enter the room from the skylight for the first time since 1941.
Today the room functions in its historic context - as a library. Today the library supports the Executive Office of the President agencies that are located within the White House Complex.