While at Fontbonne University, Cassilly met and married his first wife, painter and printmaker Cecelia Davidson. In May 1972, the couple honeymooned in Rome. They were visiting St. Peter's Basilica in Vatican City when Laszlo Toth attacked Michelangelo's The Pietà. Cassilly was the first to act and subdued Toth.[4]
While living in St. Louis, Cassilly and Davidson restored over 36 dilapidated Victorian buildings. These restorations led to the construction of six in-fill townhouses, for which he designed the architectural flourishes.[2] The Manhattan Townhouses, located at 4343 Laclede (1984) and 11-23 North Boyle (1985) in the City's Central West End, feature terracotta adorned with turtles and griffins.[5] He also designed a 12-foot-tall cast stone border fence for Cordage-Nivek's adaptive reuse of the former Dorris Motor Car building (4100 Laclede, 1985).[6] The townhouse project led Cassilly to start making sculptures professionally.[2] He soon became known for his public pieces that depict animals such as turtles and hippos.[2] The couple also built and ran a restaurant in Lafayette Square.
Eventually, they sold the restaurant, which allowed them to move to Hawaii, where Cassilly carved wooden figures.[2]
Cassilly reportedly grew tired of Hawaii and returned to his native St. Louis. There, he met sculptor Gail Soliwoda, whose works include the limestone monument at the Myron and Sonya Glassberg Family Conservation Area. Cassilly divorced Davidson and married Soliwoda.
Cassilly and Soliwoda became business partners.[2] In 1993, they bought a 250,000-square-foot (23,000 m2) complex, which included the International Shoe Building, offices and a 10-story warehouse, for 69 cents per square foot.[2] They renovated the site and opened it in 1997 as the City Museum, helping to spark a renovation boom in downtown St. Louis.[7] The museum includes a shoelace factory, a fire truck, two airplanes, and a Ferris wheel on the roof.[2] The Project for Public Spaces listed the museum among the "Great Public Spaces in the World" in 2005.[2][8] In 2002, financial obligations forced Cassilly to begin charging visitors a fee to park at the museum. Cassilly hung a sign in the museum's parking lot reading, "Greedy Bob’s Parking Lot."[2]
1999: Musical Lion Benches, University City, Missouri
Death
On September 26, 2011, Cassilly died at Cementland. A police investigation found that he died of injuries after the bulldozer he was driving flipped down a hill.[11][12] Some members of Cassilly's family contested the results of the investigation and hired an independent doctor to review the evidence. He concluded that Cassilly was beaten to death, but the St. Louis medical examiner dismissed his evidence and stood by the ruling of accidental death.[13]
Cassilly was survived by his third wife, Melissa Giovanna Cassilly, and their two children, Dylan and Robert III; and two children from his second marriage, Daisy and Max.[2]