Orfeo ed Euridice by Gluck, was written in 1762 and The Marriage of Figaro by Mozart was written in 1786. It is interesting to analyse the changes and developments from opera seria to these two examples.

During the eighteenth century, composers wrote in a style of opera called opera seria.' Opera seria had the following characteristics:

They used similar plots involving a hero and usually some sort of conflict of human passions, and these operas were often based on a story from an ancient Greek or Latin Author. The opera always consisted of three acts with alternating recitatives and arias. To show the virtuosic skill of the singer, cadenzas were used within arias. The action was created from the dialogue within the recitatives, which were accompanied by continuo and had little musical importance. There were no orchestral pieces, except for the overture and the accompaniments of the singer. It...