Alexandros Doukas Angelos Komnenos Palaiologos von Habsburg and Anemas
Philip I of Nicaea
Sophie Klementine von Habsburg
Maria III of Russia
Due to his marriage to Queen-Empress Maria, he became de jure uxoris both Emperor and Autocrat of All the Russias and King of Portugal and the Algarves.
Alexandros was born in the city of Nicaea, capital of his father's kingdom. As the only and eldest son of King Philip I and his wife Sophie Klementine von Habsburg, he became the heir to the Kingdom of Nicaea, and also the legacy of the Roman Empire, despite the fact that the Imperial Throne remained empty for many centuries. He lived primarly in the Palace of Nicaea, despite making the Palace of Epirus his residence, later in his life.
Eventually, he married Maria of Braganza, the Empress of Russia and Queen of Portugal. Due to the laws of the Portuguese constitution, he only became King when the two had their first child, but he immediatly became the Emperor of Russia after the marriage. Due to the marriage, he became de jure uxoris monarch of both Portugal and Russia.
King of Kings, Ruling Over Rulers (mentioned only)