Handel's Great Concertos ('Concerti Grossi') are not Concertos in the modern meaning of works for (usually) one Soloist and an Orchestra.
Handel generally used an Orchestra of Stringed instruments and one or two Harpsichords, and divided it into two groups of players. One group consisted of two Violins and a 'Cello, and the other comprised the remainder of the Orchestra. One Harpsichord supported each group.