In Western classical rhetoric, one of the five core disciplines was pronuntiatio, which was the art of delivering speeches. Orators were trained not only on proper diction, but on the proper use of gestures, stance, and dress. (Another area of rhetoric, elocutio, was unrelated to elocution and, instead, concerned the style of writing proper to discourse.)
Elocution emerged as a formal discipline during the eighteenth century. One of its important figures was Thomas Sheridan, actor and father of Richard Brinsley Sheridan. Thomas Sheridan's lectures on elocution, collected in Lectures on Elocution (1762) and his Lectures on Reading (1775), provided directions for marking and reading aloud passages from literature. Another actor, John Walker, published his two-volume Elements of Elocution in 1781, which provided detailed instruction on voice control, gestures, pronunciation, and emphasis.
With the publication of these works and similar ones, elocution gained wider public interest. While training on proper speaking had been an important part of private education for many centuries, the rise in the nineteenth century of a middle class in Western countries (and the corresponding rise of public education) led to great interest in the teaching of elocution, and it became a staple of the school curriculum.
An example of this can be seen in the Table of Contents of McGuffey's New Sixth Eclectic Reader of 1857 :