Answer
Théodore Chassériau, a renowned French Romantic painter, served as a close friend and mentor to Gustave Moreau. Chassériau's influence on Moreau's artistic development was significant, as he encouraged Moreau to explore the realms of mythology, allegory, and the exotic, which became defining characteristics of Moreau's later works. Chassériau's guidance and support played a pivotal role in shaping Moreau's unique artistic style and vision.