Ruben Delgaug was an artist.
He was a master artist, a painter, who was long dead by the 1360s DR.
Among his works was a set of four paintings of Waterdeep during each season, sized 8×10 inches (20×25 centimeters). These were rare and priced at 200 gp each, and 1600 gp for a full set. A set of these paintings was present at the Vipers' Nest bandit hideout in 1369 DR.