The six old schools: Eton, Harrow, Winchester, Charterhouse,
Westminster, and Rugby. Some add St. Paul's, Merchant Taylors', and
The six modern schools:
Marlborough, Wellington, Clifton, Cheltenham, Repton, and
Haileybury. Charterhouse has been removed to the hills of Surrey.
St. Paul's has migrated to the West End.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894