The violin is the highest and smallest member of the orchestral string family. The violin didn't gain real respectability as an instrument until the 17th century, having been around in its recognisable form since the mid 1500s. It had been the mainstay of popular music groups for around two hundred years and achieved its current status within the orchestra and as a solo instrument in the mid 18th century. The first player of the 1st violins is always the leader of the entire orchestra, and occupies a special place in the orchestral hierarchy. The pre-eminence of the leader reflects the position occupied by the violin as the most popular of all solo instruments.
Composers often write contrasting passages for each section of the violins.