Which forms commonly appear in the slow movements of Classical sonatas?

In Classical sonatas, the second movement typically provides a contrast to the fast first movement by utilizing a slower tempo. While the forms of these movements vary more than those of the first, the most common patterns include:

• Ternary form: A simple A-B-A structure.
• Variation form: Often presented as a theme and variations.
• Rondo: A structure where a recurring theme alternates with contrasting material.
• Sonata form: When used in slow movements, the development section is frequently omitted to maintain appropriate proportions.

The choice of form often depends on the nature of the thematic material and the degree of development already established in the first movement.1