St Isaac’s Cathedral
St Isaac’s Cathedral is one of the largest domed churches in the world and took forty years to build. Granite columns each weighing more than a hundred tonnes carry the porticoes, and the gilded dome can be seen across the whole city. The interior is filled with malachite, lapis lazuli and mosaic.
The church is dedicated to Isaac of Dalmatia, a saint on whose feast day Peter the Great was born. The present cathedral is the fourth on the site. Tsar Alexander I chose the young French architect Auguste de Montferrand, and work began in 1818. The ground was marshy, and thousands of piles were driven in to carry the building. The red granite columns from Finland were transported by sea and raised with scaffolding and winches, an engineering feat that drew spectators. The church was consecrated in 1858, the same year Montferrand died.
The cathedral has a square plan with a portico on each side, and the porticoes are carried by a total of 112 granite monolithic columns. Over the centre rises a dome on a drum surrounded by columns. The dome has a cast-iron frame, one of the first of its kind, and is gilded. Inside, the walls are clad in marble of various colours. The iconostasis has columns faced with malachite and lapis lazuli. Many of the wall images were executed as mosaic rather than painting, because the damp in Saint Petersburg ruined the paint.
After the Revolution the cathedral was closed, and in 1931 the Soviet state made it a museum of atheism. During the siege of Leningrad the dome was painted grey so as not to be a target. Since 1990 services have been held again, but the building is still administered as a museum. The cathedral is one of the last great works of Russian neoclassicism and a transition to the more eclectic style of the 19th century.