Sigiriya Mirror Wall A Gleaming White Parapet Wall Built into the Side of Sigiriya Rock
The Mirror Wall at the Sigiriya Rock Fortress in Sri Lanka, is now stained in hues of orange. When it was built by King Kasyapa over 1600 years ago it was a highly polished white masonry parapet wall that inched its way precariously along the near-perpendicular western surface of Sigiriya Rock.
Commencing at the top of a flight of steep stairs at the Terraced Gardens, it traversed a distance of two hundred meters along a gallery once covered with frescoes to a small plateau on the northern side of the rock on which the Lion Staircase is located.
The gleaming white wall provided an irresistible tablet, on which are inscribed the musings of many an intrepid traveler. These are known today as the Sigiriya Graffiti. One graffito states that the plaster was so highly polished that it reflected the fresco paintings from the opposite rock surface.
It is one of the few structures at Sigiriya which has stood partially intact for over the fifteen centuries. It is a testament to the ingenuity and workmanship of the ancient craftsman who built it.
An Ancient Parapet Wall
The Mirror Wall is a parapet wall with a two-meter-wide inner passageway. The outermost section of this passageway is built up to create a protective wall. The walkway was paved with polished marble slabs. Only about one hundred meters of this wall exists today, but brick debris and grooves on the rock face along the western side of the rock clearly show where the rest of this wall once stood.
Holes and grooves chiseled into the rock on the opposite side of the wall suggest that these were mounting points for supporting beams of a roof.
How The Mirror Wall Was Built
Faced with a near vertical rock face, the ancient builders exploited any natural indentation in the side of the rock to provide support for their wall. They did this by dropping a plumb bob (plumb line) from the proposed location of the outside of the wall until they hit a protruding rock surface however far below. At this spot, a flat niche wide enough to support at least a single brick was carved out along the entire length of the wall. Then a series of parallel grooves (see bottom photo on left), each at least a brick-width deep, were cut up the side of the rock to the point where the floor of the passageway was to be constructed.
Then a solid parapet wall of varying thickness (depending on the contour of the rock face) was built up to the height of the passageway, while some of the outer bricks were built up further to form the exterior wall. The bricks were laid slightly off horizontal—that is to say, with a slight inclination toward the rock.
This slight inclination pushes the overall weight of the structure toward the wall, giving it better adherence to the rock face. The brickwork of the wall, too, is slightly off perpendicular, leaning inward.
It is believed that its mirror-like sheen was achieved by using a special plaster made of fine lime, egg whites, and honey. The surface of the wall was then buffed to a brilliant luster with beeswax.