sentences:  In 1838, Nicholas I "pointed out" Thon's book of model designs to all architects; more enforcement followed in 1841 and 1844.Buildings designed by Thon or based on Thon's designs were Cathedral of Christ the Saviour, the Grand Kremlin Palace and the Armoury in Moscow, also cathedrals in Sveaborg, Yelets, Tomsk, Rostov-on-Don and Krasnoyarsk.Official enforcement of Byzantine architecture was, in fact, very limited