Complex sentence: On 15 December 1864, he was married in Rio de Janeiro to Princess Leopoldina of Brazil and they had four sons, with Prince Pedro Augusto of Saxe-Coburg and Gotha as eldest son.
Split into simpler sentences: On 15 December 1864, he was married in Rio de Janeiro to Princess Leopoldina of Brazil. They had four sons, with Prince Pedro Augusto of Saxe-Coburg and Gotha being the eldest son.