Because this doorway had been removed in ca. 1901, testing this theory involved excavating the plaster in the location of the ca. 1812 doorway.  Similar to an archaeology dig, the Investigation Team uncovered Montpelier’s architectural history by carefully removing individual layers of plaster starting with the most recent layers and working back to the brick or the wooden lath that supported the plaster.  Because the Team carefully excavated each layer, they could often spot changes in the different types of plaster or paint ghosts that would provide evidence for long missing architectural features.