Complex sentence: In 1918, while teaching in Geneva, Szigeti met and fell in love with Wanda Ostrowska, a young woman of Russian parentage who had been stranded by the Russian Revolution of 1917 with her sister at a finishing school in Geneva.
Split into simpler sentences: In 1918, while teaching in Geneva, Szigeti met and fell in love with Wanda Ostrowska. She was born in Russia and had been stranded by the Russian Revolution of 1917 with her sister at a finishing school in Geneva.