Complex sentence: During the late 19th century the Lancashire Plate was run at Manchester over seven furlongs and at the time was one of the most valuable races in the country, worth over £9,000 to the winner.
Split into simpler sentences: During the late 19th century the Lancashire Plate was a horse race run at Manchester. It was run over seven furlongs and at the time was one of the most valuable races in the country, worth over £9,000 to the winner.