Editing Trio sonata (section)

==Basic structure==
The trio sonata typically was written for two melody instruments (such as two violins) and [[basso continuo]].{{sfn|Van Boer|2012|loc=466}} However, either or both of the melody parts could be played on the flute, recorder, oboe, or even [[Viol|viola da gamba]].{{sfn|Vetter|n.d.}} The bass part, the continuo, typically involves two players.{{sfn|Vetter|n.d.}} One player plays the bass line on a bass instrument such as a [[bass viol]], [[violone]], [[violoncello]], or [[bassoon]].{{sfn|Vetter|n.d.}} The second player fills in harmonies above the bass line, using an instrument that can produce [[Chord (music)|chords]], such as a small [[organ (music)|organ]], a [[harpsichord]], or a [[theorbo]].{{sfn|Vetter|n.d.}} These chords are normally indicated to the player by placing numbers above the bass part rather than writing out the chords in full, a style of notation called [[figured bass]].

Because there normally are two people playing the continuo part, there are usually four players in all.{{sfn|Bonta and Zohn|2003}} This accounts for the title of [[Henry Purcell]]'s second collection, ''Ten Sonatas in Four Parts'' (1697); his first publication ''Sonnata's of III Parts''<!-- sic --> (1683) likewise included separate parts for cello and keyboard.<ref>{{IMSLP|work=10 Sonatas in Four Parts, Z.802-811 (Purcell, Henry)|work2=12 Sonatas of Three Parts, Z.790-801 (Purcell, Henry)|cname=1697|cname2=1683}}</ref> From about the middle of the 17th century two distinct types of sonatas appeared: [[sonata da camera]] (chamber sonata) and [[sonata da chiesa]] (church sonata).{{sfn|Bonta and Zohn|2003}} The sonata da camera was a suite of dances, while the sonata da chiesa had a typical four-movement structure of slow-fast-slow-fast.