The 15th-c. dance treatises of Domenico da Piacenza, Antonio Cornazano, and Guglielmo Ebreo da Pesaro contain a theoretical section in which the ratios of the tempi between the four misure of the balli are discussed. This information allows us to work out metronome markings for the four misure. When proportion signs (or mensuration signs used as proportion signs) appear in the ballo melodies, the ratio represented by these signs relates to the preceding misura.
"The Performance of Fifteenth Century Italian Balli: Evidence from the Pythagorean Ratios,"
Performance Practice Review:
2, Article 4.
Available at: http://scholarship.claremont.edu/ppr/vol6/iss2/4