The most striking monument in the Valley Forge National Historic Park is the Arch which was authorized by the Secretary of War in 1910, and transferred into the custody of the Commonwealth of Pennsylvania on June 19, 1917--the 139th anniversary of the evacuation of Valley Forge. It was designed by University of Pennsylvania professor Paul Philippe Cret. The Arch is built in a style "similar to the Arch of Titus, in Rome," and it "faces Gulph Road, over which the weary and ragged regiments marched to their camps." The Arch cost $100,000, to construct, followed by later topographical improvements for $35,000.
From the Valley Forge Historical Society:
Originally, in 1908, Congressman Irving P. Wanger of Norristown introduced a bill to Congress for federal funds for two arches at Valley Forge to honor 1-Washington and 2-Von Steuben. After much debate, the bill was amended to reduce the number to one arch to honor Washington. It was approved in Congress in 1910 and at that point they resolved that the secretary of war would oversee the project.
The designer of the architect was Paul Philippe Cret — a professor at the University of Pennsylvania. Cret was from France and studied at the Ecole des Beaux Arts. [Some of his Philadelphia structures include the Rodin Museum, the Federal Reserve Bank building and the Ben Franklin Bridge to name just a few].
The final design inspiration came from the Arch of Titus in Rome. It became controversial in some part for the fact that some people didn't want to see a triumphal arch in a rural setting. (Roman arches were always part of an urban setting). Some controversy also came up over its location, but it remained in its planned location.
The National Memorial Arch was dedicated June 19, 1917. The dedication ceremony was attended by a number of US Congressmen and hundreds of visitors. The formal address of dedication was given by then Pennsylvania governor, Martin Brumbaugh. The thought of patriotism at that time was VERY strong due to the fact the world was in chaos over WWI.
The Arch underwent an extensive renovation project the last couple of years — with funds donated by the Masons. It was rededicated with a special ceremony in 1997.