We know that there were a number of ancient sculptures showing the She-Wolf nursing Romulus and Remus - the one in the Forum, the one struck by lightning on the Capitoline according to Cicero ...
see here: the AD 360-380 mosaic at Gerona to the left, signed by Cecilianus).
The Lupercalia, celebrate in February, was last recorded in Rome in a letter written by pope Gelasius at the end of the 5th century AD attacking it. It may have continued to be celebrated even longer, with Romans seeing no contradiction between Christianity and celebrating Romulus as the founder of Rome. The festival may have continued to be celebrated for even longer in Constantinople, as a way of honouring Constantine. It was not seen as particularly pagan, but rather as part of Rome's history - and the Byzantine Emperors saw themselves as the Emperors of Rome, not as Greeks.
A Late Antique opus sectile panel from Bovillae (Latium) survives: it has lost the inserted stones, but the outline shows that the Lupa was nursing Romulus (and maybe a missing Remus).
This relief in Rome (source) is Trajanic but probably depicts the Temple of Venus and Roma built by Augustus (later re-built by Hadrian) - the wolf is shown suckling the twins in the pediment.
Although the Republican and Imperial Roman coins showing the Lupercalia are well know, they continued after the fall of the empire. These coins are part of a series issued by Theodoric and the Ostrogoths (source). The coins were issued at Rome, possibly when Theodoric visited in AD 500 and the Lupercalia was celebrated.
source). The Franks, for example Charlemagne, saw themselves as heir to the Roman Empire, so the depiction of the Lupercalia may not be surprising.
here), and ones that have regularly been found along the Silk Road (photo).
source - see for more examples).
Wall paintings from the 7th / 8th century were found in Shahristan (Bundzhikat / Panjikant), Ustrushana, another Sogdian site in Tajikistan illustrating not just the Lupercalia but more of the Romulus myth and some tales from Aesop (they're not on the Museum of Tajikistan's web site, but it's worth a look). Several western accounts confuse Shahristan / Qal'a-i Qahqaha / Pendjikent but there are two separate Sogdian palace with a she-wolf suckling twins in wall paintings.
The myth even entered the Chinese sources (JSTOR and a longer article about the Romulus myth in Central Asia JSTOR).
This post is dedicated to David Meadows who's been Tweeting me far too many questions about the statues of she-wolves suckling twins ... ;-)