Rubens was born on October 26, 1859, the oldest of four children. Santoro’s father, Giovanni Battista Santoro, was an artist and was probably himself born into a family of painters. His work can still be seen in the small coastal town of Fuscaldo where he created several altarpieces in association with other artists in his extended family. The elder Santoro, who seems to have made a reasonable living designing religious imagery, educated all of his sons to be painters; it is not known whether he also trained his only daughter, Carolina.
Rubens Santoro spent the first decade of his life in the mountain village of Mongrassano in the Calabria region of southern Italy. Although Calabria is generally a dry and dusty region, the village of Mongrassano is located in the lushly wooded Pollino mountains, making it both cooler and more fertile than much of the surrounding province. The local olive groves have been producing abundant oil since the eighth century when all of southern Italy was part of Magna Grecia. In 1869 the family moved to Naples, perhaps because there wasn’t sufficient work in Mongrassano or because there were more potential patrons in the larger city. The painter Francesco Raffaello Santoro was his cousin.