Since rhythmic durations in Renaissance music were organized in proportion to one another (differing forms of mensural notation), measures and their separating bar lines were not in use, nor were time signatures, as we know them. The rise of the “Second Practice,” ( Seconda prattica) or “New Style” ( Stile moderno) of composition (early opera) and the concomitant rise of instrumental music necessitated changes in notational practice. The crossover period between Renaissance and Baroque music at end of the 16th Century and the beginning of the 17th Century witnessed many changes as to how music was written. Use of the staff will be explained fully in Chapter 2. Bar lines serve as boundaries, defining a “measure” of music.For these examples we will employ a five-line staff. In music these groupings are delimited, or “bounded” by vertical strokes called bar lines. In Section 1.2, when describing meter and time signatures, we spoke of “grouping pulse values together” to form discrete units. Defining and recognizing sectional directions: “Roadmaps” in music.Defining and understanding measures and bar lines.
