Of the two types of Italian opera, ‘opera seria’ and ‘opera buffa’, that existed in the eighteenth century, opera seria is the one which has received more adverse comments from modern historians. The artificial division of its text and music into arias and recitative, its stereotyped plots, its concert-like and undramatic character, are easily recognised weaknesses. Musicians, moreover, have not only admired Gluck but sympathised with the sentiments expressed in his preface to Alceste and have therefore concluded that the conditions and standards he rebelled against promoted a decidedly inferior art. Perhaps for this reason a comprehensive study of the aria in opera seria has rarely been undertaken.