After leaving the interior of the Kremlin we passed by the Spaskoi [sic] Gate or Holy Gate, under which no person can pass without uncovering the head, and the Russians are so particular with regard to this that it is said, no bribe would induce one of them to pass under this gate with his hat on, were he not compelled to doff it by the Sentinel who stands always by--- The reason of its great sanctity, I cannot find.  ‘Tis dedicated to some saint I believe.  

Spassky Gate, Kremlin