The composer's name is
The Oratorio, the name of which you have just written, was first sung in the Irish city of Dublin, 1742.
At that time Sebastian Bach was living in Leipsic and had been for many years at the head of the Thomas School. He was known as its Cantor. Bach worked very hard here to supply music for several of the Leipsic churches, and he worked so well that his fame spread until it reached the ears of the Emperor.
Frederick the Great was also a musician and composer. So he invited Sebastian Bach to visit him at his castle. There were many people present, but Sebastian Bach was the principal guest. He played on many of the Emperor's fine pianos. When he reached home again he composed a musical work and dedicated it to the Emperor.
BACH PLAYING BEFORE FREDERICK THE GREAT.
The kind of a piano that Sebastian Bach played on was not called a piano in his day. It was called a Clavier or Clavichord.
Some day you will study a collection of pieces by Sebastian Bach which was written for this instrument and was called The Well Tempered Clavichord.