Simplify the following text for a Grade 10 native English-speaking person.
Original: The English country house is generally accepted as a large house or mansion , once in the ownership of an individual who also usually owned another great house in town allowing one to spend time in the country and in the city .
Simplified: The English country house is generally accepted as a large house that was once in the ownership of an individual who in most of the cases owned another great house in the West End of London .