Early Roman history includes the list of kings starting from Romulus. I assume modern historians consider Romulus legendary rather than factual, but was the last king any more historically verified than the first, and if so, where "down the list" does legend turn into history? How much of the earlier history we attribute to classical Roman chonology (overthrow of the Kings, Rape of the Sabine Women, early Consuls, Plebeian seccession, etc) is actually based in historical fact, rather than an origin legend? And how much details do we know about said events? (for example, it's one thing to accept that at one point the Romans overthrew their monarchy, and another to accept the classical historical narrative of how and why it happened).
From what I've been reading, I got the impression that the one of the earlier hard historical evidence of Roman activity was the Pyrrhic War, in which Rome established itself as a major power. But how much we actually know of Rome before then?
All and all most of Roman history before the founding of the Republic is generally considered more myth than literal truth. The founding and first few generations of Romans are shrouded in mystery and there is no real way to determine whether or not anything that happened in those years actually happened the way they are frequently told
For starters historians now believe that virtually all of the “kings” of Rome were completely legendary with little to no basis in historical fact. At best the now famous list of kings was a later invention that served as a convenient way to explain Roman institutions and practices whose origins later generations couldn’t even explain. As it we see, even Romans from the late Republic and early Empire knew little more about their own past than we do now.
As for the oldest verified historical individual we can point to, Pyrrhus of Epirus (while actually a Greek) is a good option. There is a famous statue of the Greek general that was made 200 years after his death and was likely based on an originally made during his life time. If this is true than Pyrrhus is the oldest historic figure from ancient Rome of which we can “put a face to”.
However, my money is on Lucius Cornelius Scipio Barbatus. He died around 280 BC (about 473 years after the “founding” of Rome in 753 BC) and was a Consul around 289 BC. His absurdly elaborate sarcophagus was discovered in the Tomb of the Scipios outside the original walls of Rome. His epitaph is infinitely fascinating in that it is the oldest use of the term “consul” that we are aware of and is the “earliest historical and biographical narrative to survive from ancient Rome”. (Beard, 134).
It reads as follows: “Cornelius Lucius Scipio Barbatus, offspring of his father Gnaeus, a strong man and wise, whose appearance was a match for his virtus. He was consul and censor and aedile among you. He took Taurasia and Cisauna from Samnium. He subdued the whole of Lucania and took hostages.”
So there you have it, the oldest person that we can historically verify with some degree of certainty actually existed from ancient Rome.
Primary source: "SPQR: A History of Ancient Rome" by Mary Beard
Edit: I messed up my dates for the Pyrrhic War! Barbatus died around the time of Pyrrhus invasion of Italy (280 BC) but seeing as Pyrrhus is Greek he still would not qualify as the oldest historically verified Roman. My apologies, I've had the flu so I guess no sleep and too much cold medicine will do that.