Complex sentence: A fourth marriage took place in 1175 to Matthew III, Count of Beautmont, the couple were married for seventeen years, Eleanor's longest marriage but however, they had no children and in 1192, Matthew and Eleanor divorced.
Split into simpler sentences: A fourth marriage took place in 1175 to Matthew III, Count of Beautmont. They were married for seventeen years-Eleanor's longest marriage-but they had no children and in 1192, Matthew and Eleanor divorced.