 The keys in between progressed from meantone to Pythagorean as the number of accidentals increased, with Eb and A major (the two 'intermediate' major keys) having thirds the same width as in modern 12-tone equal temperament.In effect, the 'simpler' the key, the closer it is to meantone intonation, and the more remote the key, the closer it is to Pythagorean intonation, and the 'middle' keys are similar to equal temperament.Young temperament (q.v.)