Bővebb ismertető
A Note on Dates and Spelling
Until 1918 the Russians used the Julian calendar, which runs behind our own Gregorian calendar - twelve days in the nineteenth century and thirteen days in the twentieth. This makes for awkwardness and confusion. It explains why, for example, Lenin's revolution, which took place on 25 October 1917, is now celebrated on 7 November. There is no painless way out of this situation. I myself have used the Old Style dating for internal Russian events and the New Style for external events, including wars.
A different sort of confusion may arise from the fact that the foreign brides of future Emperors, or Tsars, were required to submit to baptism into the Orthodox Church, changing their names as well as their religion. Princess Charlotte of Prussia, for example, when married to the future Nicholas I became the Grand Duchess Alexandra Feodorovna.
As for spelling, with every respect for the labours of the systematisers, it seems to be impossible to devise an entirely consistent system of transliteration from the Cyrillic to the Roman alphabet without introducing tiresome awkwardnesses and pedantries. It seems to me that so long as the meaning is clear and the spirit of our own language not affronted there is no need to worry about this. I have not felt myself bound by any hard and fast rules but have followed current usage most of the time, varying it for my own satisfaction or because of hallowed tradition - e.g. the continued spelling of Tchaikovsky instead of Chaikovsky. Christian names have been anglicised where this could be done without awkwardness.
E.G.