It’s taken a millennium for Arabic numbers—actually Indo-Arabic numbers—to replace Roman numerals, which cling to use in the Anglo-American world, but just barely. Roman numerals we still call them, because numbers were numerals a century ago. But numerals became numbers since then, while Roman numerals remained numerals, stuck a century ago, when they still retained some of their long dead glory and were used everywhere, on buildings, in footnotes, on clock faces, in the years movies were released. They get harder for us to read each year, too, harder for us to convert them to Arabic numbers in our head. Thus do the vestiges of ancient civilizations disappear.
It was just the opposite when Arabic numbers began to seep into the west in the late Medieval. They confused people, those who could read and write anyway. (You didn’t need to be literate at all to use the rather extraordinary fingering computation method used in the Middle Ages, though it’s certainly beyond me.) They couldn’t quite get the hang of what seems so perfectly natural to us now. There were bastard forms, like MCCCC92, or M4C92, or 14XC92. Worse yet was the creepily mysterious zero, which made no sense at all to most Medieval Europeans—how can something represent nothing?—thus rendering 1390 as, say, X3C1C. Unlike the introduction of the alphabet, which rendered entire literatures written in cuneiform and hieroglyphics unreadable within a couple generations, the switch to Arabic numbers took many centuries. Incredibly it was well into the 19th century that you could find Roman numerals still in daily use throughout the Anglo-American world, which is why, I suppose you can still see them affixed to old buildings or in chapter headings or the fine print of movie credits from the first half of the twentieth century. People refusing to budge from the style guides they learned in college fifty years before. You can just imagine them outraged at kids using Arabic numbers instead of the Roman numerals that had been good enough for Cicero.
But those people retired and died, and Roman numerals began to disappear from just about everything by our time (including time itself, or clock faces anyway.) Just about. The NFL, if not quite reviving the the two thousand and some year old numbers system (with origins in Etruscan numbers several hundred years earlier), has over the last half century managed to put Roman numerals into the consciousness of a couple hundred million viewers every year. Indeed, were it not for the Super Bowl—the Super Bowl, ferchrissakes, that bastion of classicism—the god damned things might have been gone and forgotten by now, except in musty academic circles or on the occasional monument. But everyone can read Roman numerals now, at least up to two Arabic number figures, which I believe would be at maximum six Roman numbers, XXXIII. This year was what, Super Bowl LV? Or as a confused Medieval football fan might have written it, X5V. Go figure.