Saint Apollonia destroys a Greco-Roman sculpture, Giovanni d’Alemagna, c. 1442-1445.
The saint calmly ascends to the ‘idol’, hammer in hand. Hagiographies frequently praised the flair with which saints smashed ancient temples and centuries-old statues.
In ‘The Most Magnificent Building in the World’, chapter six of The Darkening Age: The Christian Destruction of the Classical World, Catherine Nixey wrote:
At the end of the first century of Christian rule, the Colosseum still dominated Rome and the Parthenon towered above Athens. Yet when writers of this period discuss architecture, these aren’t the buildings that impress them. Instead, their admiration is drawn by another structure in Egypt. This building was so fabulous that writers in the ancient world struggled to find ways to convey its beauty. ‚Its splendour is such that mere words can only do it an injustice,‘ wrote the historian Ammianus Marcellinus. It was, another writer thought, ‚one of the most unique and uncommon sights in the world. For nowhere else on earth can one find such a building.‘ Its great halls, its columns, its astonishing statues and its art all made it, outside Rome, ‚the most magnificent building in the whole world‘. Everyone had heard of it.
No one has heard of it now. While tourists still toil up to the Parthenon, or look in awe at the Colosseum, outside academia few people know of the temple of Serapis. That is because in AD 392 a bishop, supported by a band of fanatical Christians, reduced it to rubble.
It is easy to see why this temple would have attracted the Christians‘ attention. Standing at the top of a hundred or more marble steps, it had once towered over the startling white marble streets below, an object to incite not only wonder but envy. While Christians of the time crammed into insufficient numbers of small, cramped churches, this was a vast—and vastly superior—monument to the old gods. It was one of the first buildings you noticed as you sailed towards Alexandria, its roof looming above the others, and one that you were unlikely to forget.
Walk on and, just behind the porticoes of the inner court, you would have found yourself in a vast library—the remnants of the Great Library of Alexandria itself. The library’s collection was now stored here, within the temple precinct, for safekeeping. This had been the world’s first public library; and its holdings had, at its height, been staggering, running into hundreds of thousands of volumes. Like the city itself, the collection had taken several knocks over the years, but extensive collections remained.
Like all statues of this size, Serapis was made of a wooden structure overlaid with precious materials: the god’s profile was made of glowing white ivory; his enormous limbs were draped in robes of metal—very probably gold. The statue was so huge that his great hands almost touched either side of the room…
To the new generation of Christian clerics, however, Serapis was not a wonder of art; or a much-loved local god. Serapis was a demon… Fierce words—but Christians had been fulminating in this way for decades and polytheists had been able to ignore them. But the world was changing. It was now eighty years since a Christian had first sat on the throne of Rome and in the intervening decades the religion of the Lamb had taken an increasingly bullish attitude to all those who refused it…
One day, early in AD 392, a large crowd of Christians started to mass outside the temple, with Theophilus at its head. And then, to the distress of watching Alexandrians, this crowd had surged up the steps, into the sacred precinct and burst into the most beautiful building in the world.
And then they began to destroy it.
Theophilus’s righteous followers began to tear at those famous artworks, the lifelike statues and the gold-plated walls. There was a moment’s hesitation when they came to the massive statue of the god: rumour had it that if Serapis was harmed then the sky would fall in. Theophilus ordered a soldier to take his axe and hit it. The soldier struck Serapis’s face with a double-headed axe. The god’s great ivory profile, blackened by centuries of smoke, shattered.
The watching Christians roared with delight and then, emboldened, surged round to complete the job. Serapis’s head was wrenched from its neck; the feet and hands were chopped off with axes, dragged apart with ropes, then, for good measure, burned.
As one delighted Christian chronicler put it, the ‚decrepit, dotard‘ Serapis ‚was burned to ashes before the eyes of the Alexandria which had worshipped him‘. The giant torso of the god was saved for a more public humiliation: it was taken into the amphitheatre and burned in front of a great crowd. ‘And that,‘ as our chronicler notes with satisfaction, ‚was the end of the vain superstition and ancient error of Serapis.‘
A little later, a church housing the relics of St John the Baptist was built on the temple’s ruins, a final insult to the god—and to architecture. It was, naturally, an inferior structure. According to later Christian chronicles, this was a victory. According to a non-Christian account, it was a tragedy…
Nothing was left. Christians took apart the temple’s very stones, toppling the immense marble columns, causing the walls themselves to collapse. The entire sanctuary was demolished with astonishing rapidity; the greatest building in the world was ‘scattered to the winds’. 
The tens of thousands of books, the remnants of the greatest library in the world, were all lost, never to reappear…
Far more than a temple had gone. As the news of the destruction spread across the empire, something of the spirit of the old culture died too. As one Greek professor wrote in despair: ‘The dead used to leave the city alive behind them, but we living now carry the city to her grave.’
 Note of the Ed.: See the remains today of the Serapeum of Alexandria: here.