Emperor Septimius Severus
Some scholars have stated that Septimius Severus was not biologically related to Emperor Marcus Aurelius, and the reason for Severus to describe himself as an heir to Marcus Aurelius was because of adoption. Again, the data above shows that not to be the case, Marcus Aurelius was, in fact, the great-uncle of Septimius Severus.
But when researching Septimius' background and genealogy, something far more interesting is revealed. He was a descendant of Justus Calpurnius Piso, and appears to be the individual known as Tertullian, the early Christian author. In the New Testament, in 'Romans 16:22', we find the name "Tert" (from "Tertius") associated with Christianity; 'I Tertius, who wrote this epistle, salute you in the Lord.'
And Pliny the Younger uses the name "Tullius" when referring to a friend of his, Tullius Justus, a.k.a. Justus Calpurnius Piso. Justus Piso was Arrius Piso's third son, and "terti" means third. That means "Tertius" would have been Justus Calpurnius Piso. He was with Pliny The Younger in Corinth, and his sister Claudia Phoebe was allowed to write a portion of the epistle 'Romans'. In the Index of Pliny The Younger, in the Loeb Classical Library edition of Pliny's Epistles and Panegyricus, Justus was referred to as "Tullius" Justus. So "Tert" from "Tertius" and "Tulli" from "Tullius" were alias names used by Justus Calpurnius Piso, ancestor of Emperor Septimius Severus.
Information given about 'Tertullian' and his family is vague. Here is what we are told about this individual - he was a prolific and very intelligent early Christian writer (Church Father), from Carthage. He was not recognized as a saint, but 'St. Jerome' said he had "lived to a great age." He was trained in juridical law and excelled at Jurisprudence (the theory or philosophy of law), more indication that he was a very intelligent individual. He wrote in both Greek and Latin and (supposedly) began writing Christian literature circa. 197 CE. His wife (which indicates that he was married at least once, perhaps more), was also 'Christian'. In my book I examine and explain how these ancient authors would designate themselves as "Christians", but were actually not Christian "believers", instead, these individuals were promoting the religion; that is, they were "Pro-Christian" writers.
During the time of Nero, there were several people who were called "Christians" when in fact, the gospels hadn't even been written yet, and neither had the epistles of 'Paul'. The people, places, and events (stories) in the Gospels were backdated to appear to have been written earlier than they actually were, and there is plenty of evidence for this, for example, the "prediction" of the destruction of the Temple in Jerusalem. The "predictions" were literary devices designed to make people think and believe in a supernatural thing.
'Tertullian's' birth and death date are only approximately known, which was common with these ancient authors, not so much though with the Roman Emperors. Tertullian was supposed to have lived circa. 160-225 CE, and we read that he was a teacher of Cyprian, which demonstrates a connection. Apparently, because of his doctrine or ideas related to Christianity, he was said to be the predecessor of 'St. Augustine', but again, with this new information, we should be thinking in terms of connection - as in commonality, perhaps even in family relationships.
We are told that 'Tertullian' was against paganism and Judaism. But, as with other Roman historians, who pretended to be indifferent to Christianity (Tacitus, Pliny The Younger), we need to consider the question - what if an emperor could write a policy that he would like to promote but do so with a pen name so that the public would never know who was actually promoting policy and various ideas. Planting ideas within the minds of the public happens even today, so as to persuade them to a certain way of thinking or to get them to think and do as a person in power desires.
The data we have so far is as follows - 'Tertullian' had taught Cyprian - he was from Carthage (North Africa) - the full name we have for him is "Quintus Septimius Florens Tertullian". We need to ask whether he really was another early Church Father whose origin and family are obscure? or was he really someone else using a created pen name, someone that we do have a lot of information on?
Septimius is a real name, it belongs to the family of Emperor Septimius Severus, an emperor that happened to be ruling at roughly the same time as Tertullian was living and writing. "Tertullian" on the other hand is a name that sounds "Roman", but no other examples of it are found, either contemporary with Tertullian or from earlier Roman history, it appears to be an invented name. Because of the genealogical data above, and what is written in the New Testament and the writing of Pliny The Younger, a combination of two names appears, both of which were used in earlier history to create aliases. "Tert" is from "Tertius" a name associated with Christianity (the author of the Epistle 'Romans') [Romans, 16:22]. "Tullius" is a name used by a friend of Pliny The Younger (Tullius Justus, aka Justus Calpurnius Piso). So both names were used by Justus Calpurnius Piso.
Let's investigate Septimius Severus further. He was born in Leptis Magna, a Roman province in Lybia, N. Africa, on April 11th, 145 CE, died Feb. 4th, 211 CE, at Eboracum, U.K. (aka now, York, England). His wives were Paccia Marciana (from 175-186 CE), and afterward to Julia Domna (of Syria). His parents were Fulvia Pia and Publius Septimius Geta. His Siblings were Publius Septimius Geta and Septimia Octavilla. His full public name of Septimius Severus was Lucius Septimius Severus Augustus. Within academia, it is commonly thought that the name gifted upon Roman royals was simply a conferred title. But in several instances, there is information showing they had the inherited right to use the name already. Septimius was succeeded by his sons, Caracalla and Geta, and he lived to age Sixty-Six, going by the birth and death dates given for him.
To end, I feel the need to include this interesting observation. Above is a medieval woodcut with the likeness of 'Tertullian'. When this image is compared to the bust of emperor Septimius Severus above, they look very much alike.