This is a term I hear thrown around a lot. People seem to associate it with 476 until the end of the Viking Age over 500 years later, and sometimes extending the age until the 1200's.
My problems lie mostly with the early phase of it. For example, if 476 is the beginning of it? Why? The answer you'll get is that Romulus Augustulus was deposed - but this is fairly silly: Romulus Augustulus, and the Western imperial throne for the last 80 years was a joke of a leadership, in fact, by 476, the worst days for Rome were behind it (Alaric's invasion, and Geiseric's invasions were fairly bad), and the period of 476 until about 541 was actually a period of growth in Rome, Germanic leaders like Theodoric actually rebuilt vast numbers of things, including aqueducts and other public works that had been left in ruin from earlier times (during the reign of the Western Roman Emperors). If I were to give a period of the Dark Ages in Italy, I would begin them in 541 when Justinian invaded and damaged the economic output so much, that it would take over 500 years to recover.
Yet, Spain and much of France in 541 had been experiencing nearly 150 years of growth, under the Visigothic Kingdom, Roman culture had been recovering from the time of the Vandal invasion in 406 AD (again, before the date of 476). In fact, during this period, the Visigoths not only aided in the recovery of the Western provinces of the Empire, but they also built new cities; not even the Eastern Romans were doing this during these years. It wasn't really until the wars between the Islamics and Christians beginning in the 8th century that the Dark Ages could really have been said to have started in Spain - and this is roughly the time where the Dark Ages also began in the Eastern Roman Empire - and where the transition from Eastern Roman to Byzantine culture occurred.
England is a different story, clearly the Dark Ages were earliest here, with Saxons invading well before the 476 date. Yet, those same Saxons built quite an interesting society.
OK, so we have this period now from the mid 7th century to the year 1000. Yet, after 800, Byzantine culture rose up, and this could hardly be called a Dark Age period. The Islamic Caliphates were also seeing a golden age of reason and enlightenment. Even in the west, before the Vikings, the Frankish Empire had obtained enough power to sever political ties to Constantinople, and began rebuilding schools and other public works (particularly under Charlemagne). Is this really a dark age? Sure, in some parts of Europe there was Darkness, but the point I am trying to make is that this was NOT a period of total darkness like in the Greek Dark Ages after the fall of Mycenae and Knossos. Rather, I think if anything, Late Antiquity can be said to be the era from the rise of Diocletian in 284AD (The Roman Empire in the 4th century was actually more powerful and effective than it was in the 3rd century) until the Battle of Guadalete in 711 AD, when the Visigothic Kingdom fell. Since this era is so close to the Battle of Tours in 732 where the Franks repulsed the invasion of France, and the Franks themselves had already been rebuilding and ressurecting Europe, I wouldn't want to call 711 the beginning of the Dark Ages.
More like the Early Middle Ages, because it was during this period of Islamic and North Germanic (Viking) invasions that Eruope really became militarized and very much a warrior society (Knights and all); but this is the Middle Ages; and it was a general period of economic recovery from the Viking invasions onward until an explosion began in Florence, which we can call the Modern era.
I describe myself as a little dose of toxic masculinity.