The Difference Engine: one man, many lives, same difference

Imagine modern day England under Soviet rule; Caliphate rule; Nazi Rule; Roman rule
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In 1961, the first manned Soviet space flight successfully orbits the Earth. In 1191, Christian crusaders defeat Saladin but turn back before Jerusalem. In 1939, the Führer gives his beer hall speech before planning the invasion of Europe. In 61, the Iceni lose a great battle to rid their lands of its Romani invaders.

Except that none of these events ever took place.

I am Gillan Pots: farmhand in Soviet Britain; fighter in the English Emirate; official of the British Reich; plebeian in Imperial Brittania. I have lucid dreams of a different world, one that is more real to me than these substitute lives, and all I want is for the echoes through time to stop picking at my addled brain. But the engine of the universe is not so forgiving: it has other plans for me as it keeps re-gearing the world, and all so that I can be the difference.