Answer
Neoclassicism, characterized by a return to traditional forms and techniques of the 18th century, initially dominated Andriessen's work. This musical period influenced his early compositions, incorporating elements such as clear textures, balanced structures, and a focus on melody. Andriessen's neoclassical style reflected a desire to revive and reinterpret classical traditions in a contemporary context, shaping the foundation of his musical language during this phase of his career.