Drusus Julius Caesar
Besides the inscriptions mentioning his consulship, Pontianus had a monument built at Tusculum in memory of his grandmother, Rubellia Bassa, the daughter of Gaius Rubellius Blandus and Julia. Rubellia's father was from a rather obscure family, but he had been consul in AD 18. Her mother, Julia, was the daughter of Drusus Julius Caesar, the natural son of Tiberius, and Livilla, a grandniece of Augustus. Few of Pontianus' contemporaries could have claimed descent from the Julio-Claudian Dynasty. One possible exception was Sergius Rubellius Plautus, whose name has been found on a lead pipe at Rome; he may have been a son of Blandus and Julia, or perhaps another relative.