Titania is the largest moon of Uranus, with a diameter of 1, 578 km. It was discovered in 1787 by William Herschel and is the eighth-largest moon in the Solar System. It is composed of roughly equal parts water ice and rocky material and is the only large moon in the Solar System with a retrograde orbit. Titania is named after the queen of the fairies in Shakespeare's A Midsummer Night's Dream.