Why call Formidable a sovereign battleship?

The term pre-dreadnought can obscure how contemporaries understood these ships, since Dreadnought had not yet been built when Formidable entered service. In the terminology used here, the Royal Sovereigns begin a recognisable mature battleship form that successive classes improved until Dreadnought combined several existing developments into a new type. The retrospective label is especially awkward because Britain completed ships now called pre-dreadnoughts after Dreadnought herself. This distinction separates historical categories from later labels of convenience. HMS Renown remains outside the sequence as an unusual design pointing toward the battlecruiser.