In the Baroque music era (1600–1750), most orchestras were led by one of the musicians, typically the principal first violin, called the concertmaster. The concertmaster would lead the tempo of pieces by lifting his or her bow in a rhythmic manner. Leadership might also be provided by one of the chord-playing instrumentalists playing the basso continuo part which was the core of most Baroque instrumental ensemble pieces. Typically, this would be a harpsichord player, a pipe organist or a luteist or theorbo player. A keyboard player could lead the ensemble with his or her head, or by taking one of the hands off the keyboard to lead a more difficult tempo change. A lutenist or theorbo player could lead by lifting the instrument neck up and down to indicate the tempo of a piece, or to lead a ritard during a cadence or ending. In some works which combined choirs and instrumental ensembles, two leaders were sometimes used: a concertmaster to lead the instrumentalists and a chord-playing performer to lead the singers. During the Classical music period (ca. 1720–1800), the practice of using chordal instruments to play basso continuo was gradually phased out, and it disappeared completely by 1800. Instead, ensembles began to use conductors to lead the orchestra's tempos and playing style, while the concertmaster played an additional leadership role for the musicians, especially the string players, who imitate the bowstroke and playing style of the concertmaster, to the degree that is feasible for the different stringed instruments.