The term "Dark Ages" for the time period immediately after the end of the Western Roman Empire was first characterized by the fourteenth-century Italian scholar Francesco Petrarca, commonly known as Petrarch. The general consensus in Christian Europe during that time was that Classical Antiquity (the time period of Ancient Greece and Rome) was an age of darkness due to the absence of the Christian faith. Petrarch was the first to co-opt the metaphor and give it secular meaning by reversing its application. Petrarch saw the Roman Empire as a high point of culture and Italian greatness. Classical Antiquity was now seen by Petrarch as the age of light because of its cultural achievements, while Petrarch's time, allegedly lacking such cultural achievements, was seen as the age of darkness.

Petrarch believed that there were two historical ages: the Classical age of Greece and Rome and the less-refined, darker age that he saw himself currently living. In his epic poem Africa, written about 1343, he wrote:

"My fate is to live among varied and confusing storms. But for you perhaps, if as I hope and wish you will live long after me, there will follow a better age. This sleep of forgetfulness will not last forever. When the darkness has been dispersed, our descendants can come again in the former pure radiance."

About one hundred years later the fifteenth-century Italian historian Leonardo Bruni, living at the height of the Italian Renaissance, added onto Petrarch's two-age outline of history and added a third, Modern Age as Bruni felt Italy had revived itself just as Petrarch hoped it would. Since Bruni felt there were three ages of history, he chose to identify the time period between Antiquity and Bruni's own Modern Age as media tempestas or "middle season". In 1604, Bruni's Middle Season was referred to as medium aevum, or "middle age" (medium aevum is also where we get the term medieval). 1625 was the first recorded use of the term media saecula, or "middle ages". Historians began to further subdivide the Middle Ages into three intervals: "Early" (fifth-century to tenth-century), "High" (tenth-century to thirteen-century), and "Late" (thirteen-century to fifteenth-century), but with the common adoption of these subdivisions, use of the term Dark Ages eventually was restricted to the Early Middle Ages.

Generally speaking, however, historians do not use the term "Dark Ages". Instead, Classical Antiquity ends during the Roman Empire's Crisis of the Third Century (about 235-284 CE) with the time period called "Late Antiquity" starting then and ending somewhere during the reign of the Frankish king Charlemagne (774-814) leading into the Middle Ages.