The city of Rome traditionally regards April 21, 753 BC as the date of its founding by Romulus, and therefore marked its first millennium of existence in April of 248 AD. A custom which is only sporadically attested in the Republican period had it that the city’s founding be commemorated with a special set of theatrical and gladiatorial games known as the “Ludi Saeculares.” But in this context, “saeculum” could be taken to mean either 100 years or 110, depending on which span was believed to be definitively greater than the maximum possible length of a human life. They were therefore scheduled in such a way that in theory, no man could ever see them twice. But different calculations gave rise to different cycles, and in any case, in the chaos of the late Republic, they were apparently allowed to lapse.
The Emperor Augustus revived them in 17 BC, but they were repeated by Claudius in 47 AD for Rome’s 800th anniversary, when only 64 years had passed. Suetonius notes this event as follows:
“Fecit et saeculares, quasi anticipatos ab Augusto nec legitimo tempori reservatos, quamvis ipse in historiis suis prodat, intermissos eos Augustum multo post diligentissime annorum ratione subducta in ordinem redegisse. Quare vox praeconis irrisa est invitantis more sollemni ad ludos, quos nec spectasset quisquam nec spectaturus esset, cum superessent adhuc qui spectaverant…
He also celebrated the Secular Games, alleging that they had been given too early by Augustus and not reserved for the regular time, although he himself writes in his own History that when they had been discontinued for a long time, Augustus restored them to their proper place after a very careful calculation of the intervals. Therefore the herald’s proclamation was greeted with laughter, when he solemnly invited the people ‘which no one had ever seen or would ever see again’, for there were some were still living who had seen them before… ” (Divus Claudius 21, 2)
(A silver coin minted under Philip the Arab to commemorate Rome’s millennial anniversary.)

The emperor in 248 AD is known as Philip the Arab, since he was born in the Roman province of Arabia, in the region known as Aurantis (Hauran), in the southwest of the modern state of Syria. One of the primary sources for the events of his reign is the strangely untrustworthy work known as the Historia Augusta, which is quite hostile to him. This is its account of Philip’s Secular Games.
“Fuerunt sub Gordiano Romae elephanti triginta et duo, quorum ipse duodecim miserat, Alexander decem, alces decem, tigres decem, leones mansueti sexaginta, leopardi mansueti triginta, belbi, id est hyaenae, decem, gladiatorum fiscalium paria mille, hippopotami sex, rhinoceros unus, argoleontes decem, camelopardali decem, onagri viginti, equi feri quadraginta, et cetera huiusmodi animalia innumera et diversa; quae omnia Philippus ludis saecularibus vel dedit vel occidit.Has autem omnes feras, mansuetas, et praeterea efferatas, parabat ad triumphum Persicum. quod votum publicum nihil valuit; nam omnia haec Philippus exhibuit saecularibus ludis et muneribus atque circensibus, cum millesimum annum in consulatu suo et filii sui celebravit.
(A mosaic depicting theatrical spectacles, gladiatorial and animal combats, ca. 80 AD; discovered in Roman villa near the ancient city of Leptis Magna, near Tripoli. Public domain image from Wikimedia Commons.)

In the time of Gordian (Philip’s predecessor), there were thirty-two elephants at Rome, of which he himself had sent twelve, and Alexander (Severus) ten, ten elk, ten tigers, sixty tame lions, thirty tame leopards, ten ‘belbi’ or hyenas, a thousand pairs of imperial gladiators, six hippopotami, one rhinoceros, ten wild lions, ten giraffes, twenty wild asses, forty wild horses, and various other animals of this nature without number. All of these Philip presented or slew at the secular games. All these animals, wild, tame, and savage, Gordian intended for a Persian triumph; but his official vow proved of no avail, for Philip presented all of them at the secular games, consisting of both gladiatorial spectacles and circus races, when he celebrated the thousandth anniversary of the founding of the City, when he and his son were consuls.” (Gordiani Tres, 34)