Final answer:
Pablo Picasso transitioned from a late Romantic to a modernist, becoming a leading figure in the Cubism movement and influencing modern art in various forms.
Step-by-step explanation:
The artist who began as a late Romantic and transformed into a modernist is Pablo Picasso. Picasso, initially influenced by late Romantic movements, evolved his style over time, eventually pioneering Cubism, a significant modernist movement. His journey from his Blue Period to the Rose Period and ultimately to the founding of Cubism demonstrates his progression. One of Picasso's most famous works, Les Desmoiselles D'Avignon is a prime example of his modernist approach, depicting multiple perspectives within a single composition. Throughout his career, he remained inventive, contributing not only to painting but also to sculpture, ceramics, and other art forms.