École Spéciale d'Architecture (Bordeaux Architectural College). On his return to the US he then shared the influence with Washington, Hoban, Monroe, and Benjamin Henry Latrobe. Construction Construction of the White House began at noon on October 13, 1792, with the laying of the cornerstone. The main residence, as well as the foundations of the house, were built largely by enslaved and free African-American laborers, as well as employed Europeans. Much of the other work on the house was done by immigrants, many of them without citizenship yet. The sandstone walls were erected by Scottish immigrants, employed by Hoban, as were the high-relief rose and garland decorations above the north entrance and the "fish scale" pattern beneath the pediments of the window hoods. There are conflicting claims as to where the sandstone used in the construction of the White House originated. Some reports suggest sandstone from the Croatian island of Brač, specifically the Pučišća quarry whose stone was used to build the ancient Diocletian's Palace in Split, was used in the original construction of the building. However, researchers believe limestone from the island was used in the 1902 renovations and not the original construction. Others suggest the original sandstone simply came from Aquia Creek in Stafford County, Virginia, as importing the stone would be too costly. The initial construction took place over a period of eight years, at a reported cost of $232,371.83 (). Although not yet completed, the White House was ready for occupancy circa November 1, 1800. Due in part to material and labor shortages, Pierre Charles L'Enfant's plan for a grand palace was five times larger than the house that was eventually built. The finished structure contained only two main floors instead of the planned three, and a less costly brick served as a lining for the stone façades. When construction was finished, the porous sandstone walls were whitewashed with a mixture of lime, rice glue, casein, and lead, giving the house its familiar color and name. Architectural description The main entrance is located on the north façade under a porte cochere with Ionic columns. The ground floor is hidden by a raised carriage ramp and parapet. The central three bays are situated behind a prostyle portico that was added circa 1830. The windows of the four bays flanking the portico, at first-floor level, have alternating pointed and segmented pediments, while the second-floor pediments are flat. A lunette