Claudia Octavia

Claudia Octavia (late 39 or early 40 – June 9, AD 62) was a Roman Empress. She was the daughter of the Emperor Claudius and Valeria Messalina. 
Her mother died and her father re-married her cousin Agrippina the Younger. So she became the stepsister of the future Emperor Nero. She would also become his wife. The marriage was arranged by Agrippina.
Octavia was popular with the people of Rome. But Nero hated their marriage. When his mistress, Poppaea Sabina, became pregnant, he divorced Octavia, and banished her. When this led to a public outcry, he had her executed.