Complex sentence: Her younger sister Princess Nino married the famous Russian playwright, composer and diplomat Aleksandr Griboyedov, and her older sister Sophie was married to Count Alexandr Nikolai, the minister of education of Imperial Russia.
Split into simpler sentences: Her younger sister Princess Nino was married to Aleksandr Griboyedov, a famous Russian playwright, composer, and diplomat. Ekateriné's older sister Princess Sophie was married to Count Alexandr Nikolai, the minister of education of Imperial Russia.