I’ve been trying to understand Sir Alex Ferguson’s effect on Manchester United, and to do so I have had to go back in time.

About half my life ago – well, seventeen years back, but it sounds more grand when I express it as a fraction – I studied Medieval History at school. It was a privilege to take that course. You see, I think that Medieval History – roughly everything from about 500AD to 1500AD – gave me pretty much everything I needed to appreciate why our world has turned out like it has. Ancient History, with its impossibly wise Greeks and long-deserted pyramids, always felt a little too remote; and by the time you got to Modern History, to Western empire, Nazis, and the nuclear bomb, it all felt like the wheels were well in motion, and that there was little more that you could learn about the roots of all this. But Medieval History? It was all Vikings, Crusades and international trade, slavery and Christianity, Islam, Rome and Constantinople. This, I felt, was when the ball of modern history was truly set rolling.

Increasingly, I feel like there are three ages of Manchester United: ancient, middle and modern. The ancient history of the club, in my mind (or, at least, in my heart) was everything that occurred until the early Eighties, right before the arrival of Fergie. Being only thirty-three, I look back on everything prior to that with respect, but with a sense of distance. The names of the Busby Babes have the beautiful and painful echoes of legends long gone; those players and their true marvels are unknowable to me as the original wonders of the world.

The middle age of Manchester United, as I see it, is pretty much everything from the early Eighties to, I would say, the turn of the 21st century. During that time, its supporters came to treat success if not quite as a birth-right then certainly as an expectation. In the two years following the Treble, the club added footnotes to its tale of domestic dominance, completing a hat-trick of league titles.
And now we are in the modern age of Manchester United. In this age, we have witnessed the startling emergence of new and sustained challenges to Old Trafford’s hegemony. The greatest threats, more so than Arsene Wenger’s Arsenal or Liverpool under Rafa Benitez, have come from Manchester City and Chelsea. The latter club, under Jose Mourinho, looked for a time as if they would extinguish every opponent in sight, which is why Manchester United’s title triumph in 2006-07 – which, by no accident, coincided with the arrival of Michael Carrick – is perhaps Ferguson’s greatest victory of this period. Running that achievement close is the league championship that Ferguson narrowly claimed ahead of Chelsea in 2010-11, that year when Wayne Rooney launched himself airborne in the local derby.

Why does all this matter? Well, because it’s unheard of in history to have a dominion that lasts through three ages. After all, Ferguson has been in charge at Old Trafford for 26 years, or about one-sixth as long as the entire sport of association football has been in existence. The only thing I saw in Medieval History with the same sort of epic longevity as Ferguson’s reign was the Byzantine Empire, which ran pretty much unchecked for about a thousand years. During the course of that millennium, the Byzantine Empire saw off all manner of opponents. Central to its success was Constantinople, its capital; from the day of its founding in 330AD, it was understood that whoever overwhelmed this forbidding city would take control of the empire. So it was that, when the Turks sacked Constantinople in 1453, the Byzantine Empire also fell; and it gave way to the Ottoman Empire, which would hold sway for five hundred years.

As it was with Constantinople, so I thought it would be with Old Trafford: once the home terrain fell, then so would everything else. The Theatre of Dreams has a rare aura that is the foundation of so many of its victories; and that’s why, when Manchester City eviscerated us by six goals to one, I genuinely thought that the club had lost its mystique. Being dethroned as champions by Sergio Aguero’s late goal was not so agonising as this defeat.

I should have had more faith, I know, that Sir Alex Ferguson would restore us to the peak. It’s just that, as history tells so often us, there are very few forces that come back from a reverse as resounding as that. After all, the Trojans were toast after that horse got past their walls. Napoleon was done for after Waterloo. Yet, after that bloodletting at Old Trafford, Fergie managed to rouse his men again, for a campaign more compelling than most he has mounted.

This season, in many ways, has been as remarkable as any in which the great Scot has been in charge. On one hand, it has been thoroughly modern: in an age where the average full-back is more valued for his attacking rather than defensive contribution, Ferguson has put his faith in firepower rather than a tight rearguard. On the other hand, it has been reassuringly ancient: the resilience Manchester United have shown in coming back so often is in the finest traditions of the club, reaching back to the glorious era of Sir Matt Busby.

When football’s historians come to consider this period at length, they will remark at length on Sir Alex Ferguson’s tactical nous, and his ability to motivate his players. But what will give them greatest cause for respect is the incredible ability that he has shown to renew his team year after year, decade after decade. Indeed, Ferguson has been so good for so long that, if football were a Bible, then he would have a starring role in both the Old and the New Testament: and few can say fairer than that.

Follow Musa Okwonga on Twitter and check out his other work on his website (and his Hail to the Tempest poem about Roy Keane).