sentences:  Vivaldi's concertos firmly establish the three-movement form as the norm.The virtuosity of the solo sections increases markedly, especially in the later works, and concurrently the texture becomes more homophonic.Concertos for instruments other than violin began to appear early in the 18th century, including the oboe concertos of George Frideric Handel and the numerous concertos for flute, oboe, bassoon, cello, and other instruments by Vivaldi.