The harp is an ancient instrument, probably originating from the bows used by hunters. The ancient Egyptians used highly elaborate harps, as did the ancient Greeks and Romans. Today's harp used in the symphony orchestra has 46 strings, and a huge range of 6 1/2 octaves. Seven pedals are used to raise the pitch of all instances of each of the 7 notes in the diatonic scale by a semitone.
Handel used harps in some of his operas. Mozart wrote his flute and harp concerto in 1778, and Berlioz used it to great effect in his Symphonie Fantastique.