The "Italian" style of symphony, often used as overture and entr'acte in opera houses, became a standard three-movement form: a fast movement, a slow movement, and another fast movement. Over the course of the 18th century it became the custom to write four-movement symphonies, along the lines described in the next paragraph. The three-movement symphony died out slowly; about half of Haydn's first thirty symphonies are in three movements; An outstanding late example of the three-movement Classical symphony is Mozart's "Prague" Symphony, from 1786.