Complex sentence: Centered around the then capital Petrograd (modern day St. Petersburg) in March (late February in the Julian calendar) its immediate result was the abdication of Tsar Nicholas II, the collapse of Imperial Russia and the end of the Romanov dynasty.
Split into simpler sentences: Centered around the then capital Petrograd (modern day St. Petersburg) in March (late February in the Julian calendar). Its immediate result was the abdication of Tsar Nicholas II, the collapse of Imperial Russia and the end of the Romanov dynasty.