When did frequent tempo directions begin appearing in written European music?

Frequent tempo directions began appearing in written European music starting in the 16th century. While isolated examples of speed indications exist as early as the 9th century in plainsong manuscripts, these were exceptional because the repertoire was already familiar to performers.1

The shift toward frequent tempo instructions occurred primarily in 16th-century collections that featured a wide variety of musical forms and styles, such as the lute books of Hans Neusidler or the vihuela publications of Luis Milán. These early, often descriptive directions eventually evolved into more methodical systems. By the 17th century, composers began using the Italian terms—such as adagio, largo, and presto—that have remained in use to describe tempo ever since.12

Prior to the 17th century, Western classical music rarely utilized explicit tempo markings, as the speed of a piece was typically determined by fixed pulse, mensuration, and note values.3