Simplify the following text for a Grade 4 native English-speaking person.
Original: Umbriel , along with another Uranian satellite , Ariel , was discovered by William Lassell on October 24 , 1851 .
Simplified: Umbriel is a moon of Uranus found on October 24 , 1851 by William Lassell . It was found at the same time as Ariel .