earlier the amount by which the dot augmented the note varied: it could be more or less than the modern interpretation, to fit into the context.

The vertical double dot was introduced by Willi Apel and is commonly used in modern transcriptions of medieval and renaissance music. It lengthens an already dotted note by half: a dotted half note (minim) consisting of 6 quarter notes becomes 9 quarters when vertically double-dotted. This greatly simplifies modern notation (which otherwise would require a dotted half note tied to a dotted quarter