Different strokes for different folks? On tempo and diminution in fifteenth-century music

The stroke in the mensural notation sign Tenor sign with vertical line (which turns up in musical sources shortly after 1400) has generally been understood to signal diminution in perfect tempus. According to a new interpretation advanced by Margaret Bent, however, this was not its primary meaning until the later fifteenth century. Before then, she has argued, Tenor sign with vertical line was in use as a "general-purpose sign," with a broad range of meanings of which diminution was only one. This interpretation is open to challenge on both factual and methodological grounds. At present, there appears to be no basis for abandoning the received interpretation of Tenor sign with vertical line.