Guido of Arezzo
In the 12th century, a development in teaching and learning music in a more efficient manner had arisen. Guido of Arezzo's alleged development of the Guidonian hand, more than a hundred years after his death, allowed for musicians to label a specific joint or fingertip with the gamut (also referred to as the hexachord in the modern era). Using specific joints of the hand and fingertips transformed the way one would learn and memorize solmization syllables. Not only did the Guidonian hand become a standard use in preparing music in the 12th century, its popularity grew more widespread well into the 17th and 18th century. The knowledge and use of the Guidonian hand would allow a musician to simply transpose, identify intervals, and aid in use of notation and the creation of new music. Musicians were able to sing and memorize longer sections of music and counterpoint during performances and the amount of time spent diminished dramatically.
Bass violin
The viol, or "viola da gamba," was introduced to Italy from Spain around 1490. Before the introduction of the viol, no bowed instrument existed in the region The viol da gamba was played in the "a gamba" position (i.e., between the legs like a cello, as opposed to under the chin like a violin). The "viola da gamba" was also much larger, and therefore could play much lower notes than other fiddles in Italy at that time. The first Italian viols (or ""violoni"" as they were often called) soon began to take on many characteristics of the precursors to the violin, such as separate tail pieces, and arched bridges that let the player sound one string at a time. (Though paintings like Jan Brueghel the Elder's "The Rustic Wedding" and Jambe de Fer in "Epitome Musical" suggest that the bass violin had alternate playing positions, these were short-lived and the more practical and ergonomic "a gamba" position eventually replaced them entirely.) One of the qualities that was almost certainly adopted by the Italian violin makers from the early Spanish viols was the C-bout, which they soon stylized. At some point in the early to mid-sixteenth century, an Italian maker (possibly Amati) set out to create a "violone" that was more closely matched, in appearance, tuning, and number of strings, to the new violin. Judging by artistic representations of the period, this may have been a somewhat gradual development. For example, there are depictions of instruments that appear to be bass violins (such as the one in Gaudenzio Ferrari's "Glory of Angels", 1535), but that clearly show the presence of frets. Once the distinction became clear, and the form of the bass violin had crystallized, theorists and composers began to refer to the new instrument as the ""basso da viola da braccio"", or the first true bass violin.