Tonal music and metre
Musical rhythm deserves a whole web site not a footnote, but this page briefly outlines the importance of metre to the various voiceleading characteristics described in the Toolkit.
As shown by the accents in the example below, convention dictates that certain beats of the bar are stressed more than others, according to the time signature
The particular relevance of this to tonal music is that dissonant notes are more or less prominent depending on whether or not they appear on stressed beats. In the following example, the dissonances (marked with stars) are therefore more prominent when they coincide with a a stressed beat of the bar (marked with accents). Many of the rules of voice-leading are affected by the relative prominence of dissonance - see for example the passing note.