Simplify the following text for a Grade 1 native English-speaking person.
Original: Boxer is also the name of a dog owned by John Peerybingle , the main character on the best selling 1845 book The Cricket on the Hearth by Charles Dickens , which is evidence that `` Boxer '' was commonly used as a dog name by the early 19th century , before the establishment of the breed by the end of that same century .
Simplified: Boxer is a dog breed .