<Ol> <Li> In the earliest stages, these simple intervals occur so frequently that they appear to be the favourite sound of composers . </Li> <Li> Later, the more "complex" intervals (thirds, sixths, and tritones) move gradually from the margins to the centre of musical interest . </Li> <Li> By the end of the Middle Ages, new rules for voice leading had been laid, re-evaluating the importance of unison, octave, fifth and fourth and handling them in a more restricted fashion (for instance, the later forbidding of parallel octaves and fifths). </Li> </Ol> <Li> In the earliest stages, these simple intervals occur so frequently that they appear to be the favourite sound of composers . </Li> <Li> Later, the more "complex" intervals (thirds, sixths, and tritones) move gradually from the margins to the centre of musical interest . </Li> <Li> By the end of the Middle Ages, new rules for voice leading had been laid, re-evaluating the importance of unison, octave, fifth and fourth and handling them in a more restricted fashion (for instance, the later forbidding of parallel octaves and fifths). </Li>

What pitch is a perfect fourth (p4) above g#