Vibia Sabina (83–136/137) was a Roman Empress, wife and second cousin, once removed, to Roman Emperor Hadrian. She was the daughter to Salonina Matidia (niece of Roman Emperor Trajan), and suffect consul Lucius Vibius Sabinus.
She married Hadrian in 100, at the Roman Empress Pompeia Plotina's request, for Hadrian to succeed her great uncle, in 117. Sabina's mother Matidia (Hadrian's second cousin) was also fond of Hadrian and allowed him to marry her daughter.
Sabina was strong and independent and her beliefs in marriage didn't sit well with the Emperor. Sabina had an affair with Suetonius, a historian (and Hadrian's secretary), in the year 119. In 128, she was awarded the title of Augusta.Vibia Sabina in Wikipedia