Why did Peter Paul Rubens collect ancient Roman sculptures and coins?

Peter Paul Rubens collected ancient Roman sculptures, reliefs, portrait busts, and coins primarily as a result of his deep commitment to scholarship and his identity as a learned humanist and antiquarian.12

During his second trip to Rome, beginning in 1605, Rubens and his brother Philip undertook an intensive study of ancient art and philology. This profound academic interest allowed him to draw upon a vast wellspring of Greek and Roman history and mythology, which served as a vital foundation for the subject matter and iconography of his own art. His collection was not merely a passive hobby; it was an extension of his intellectual life, reflecting his embodiment of the Renaissance man who integrated classical traditions into the vibrant, dynamic style of the 17th-century Baroque era.21