Hi there! Well, in all honesty, the "Dark Ages" narrative of the middle ages is an outdated tag; the middle ages as some sort dark warlord-run backwater is very much an intellectual invention of the late 15th/early 16th centuries. I actually don't even like the terms "Middle Ages," or even "Renaissance." Although broad historic periods can, with care, be outlined, I find periodization has limited use. I, for one, am interested in Communal Italy: that is to say political institutions, economic characteristics, and social identity in Italian cities. This is a theme which, although certainly most notable and indeed particularly interesting between the twelfth and fourteenth centuries, is rooted in characteristics which developed much earlier and which remained impactful for many centuries thereafter.

That having been said, although I'm not a historian of antiquity, I don't feel like Italy in centuries like the eleventh is less documented than it had been during, say, the Roman Empire. In spite of the "dark" reputation, centuries like the 11th have a whole bunch of chronicles narrating what was going on, in addition to artistic and archeological evidence to work with. In this admittedly long answer from earlier today, I mention Landolfo Seniore, a high officer of the Bishopric of Milan; Arnulfus Mediolanensis, an earlier high officer of the Bishopric of Milan; and the Honorantie civitatis Papie, Ottonian-era tax records. But we needn't stop there, the previous century there are chronicles by Liutprand in Cremona and the Deacon John in Venice to consult. In the twelfth century, there are also anonymous chronicles and written accounts penned by the growing Italian middle class; as well a number of works which have only been transmitted down to us in incomplete form: a bureaucrat in twelfth-century Milan, known only as Sire Raul, composed Annales Mediolanenses citing a number of lost works, including two presumed firsthand accounts of the Battle of Legnano.

Although there are a disproportionate amount of clergymen writing these chronicles, over the course of the twelfth century there is indeed growing representation of the bureaucrato-administrative class, an elite selected from the lawyers and jurists who already constituted the upper middle class of the Italian cities. In addition to Sire Raul, Ottobono of Genoa and Salimbene of Parma are two additional important examples of sources for the Italian perspective of the conflict between the Emperor Barbarossa and the Italian cities.

In addition to outright chronicles, there are also legal records. We can sometimes even trace the arrival, rise, and fall of individual families within an individual city: there is one dynasty, the Caronia, who appear as landowners in the vicinity of Monza in the tenth century. They relocate to Milan sometime after Emperor Conrad the Salian makes the milanese bishop his imperial vicar. The Caronia reappear most prominently at the end of the eleventh century, witness in a court case. However they are now referred as Capitani di Porta Romana, one of the most important offices in the city. They go as far as to identify the witness, one Alberto, solely by his title: di Porta Romana. How do we know this is the same family? Alberto's son (Alberto Jr.) went to notarize his inheritance, and is identified as Albericus filius quondam item Alberici qui fuit dictus Carrognia (Alberto, son of the aforementioned Alberto, called Caronia). The Caronia continue to appear in court documents and legal records until the 14th century, most of the time identified with their title, but sometimes through one of the variant spellings of their surname, like Carrognia, Carronia, or Carronnia. Cross-checking these documents with the highly opinionated but nonetheless invaluable chronicles written by people like Landolfo and Arnulfus is an important process in constructing what life and society was like.

And these are just examples in Lombardy! There are many more chronicles dealing with Rome, the Papacy, and indeed the rest of Europe.