Romanos II (1823 - 1891) was King of Nicaea and Co-Regent of Constantinople from 1865 to 1885, succeeding his older brother Alexios I. He was the second and youngest son of Romanos I and of Theodora Psellina. He married Theophano Anemas, a distant relative of his, and the two had a son, Alexios, who would succeed his father as Alexios II. According to the Encyclopædia Veneficia, Romanos II became a member of the Roman Regency Council in 1864. When the Encyclopaedia was published in 1890, he already was the head of the Council.