Anyway, the Old Ones were eventually defeated locked up in prisons in reality, although some may have been cast out. We don't know enough about that time to be sure. Presumably star born helped with this, and it all seems to do with the Cycle (a loop of events that includes the 666 year conjunction that creates star born and some other event where the balance of power is reset and/or the Outsiders get a good chance to come in). Some call it the Game.
I'm not sure if we have a firm year for the Dresden Files, but 666ish years before DF gives us a bunch of really, really important events.
1. The Renaissance kicks off; Dante's Divine Comedy, Botticelli, etc.
2. The Black Death wipes out anywhere from 50-200 million people, upwards of 1/4 of the world's population (which sounds awfully apocalyptic, and I'm pretty sure Nicodemus was involved; it could very well have been hijacked from Outsiders).
3. Probably not relevant right now, but this is around the time the Aztec empire really started (it's around this point that one of the main city-states, Tenochtitln, was established; it's unclear when exactly it was founded, but 1325 is often the cited date). Basically, this is around the time that we start having a clearer picture of what the various Mexica city-states and civilizations were doing. Expansion, war, sacrifice, etc. I don't know how relevant this might be in the future, because the only thing close to the Aztec we've seen in the series are Kukulcan and the Yucatan after they were hijacked by the Red Court.
4. The Hundred Years War kicks off. Joan of Arc isn't around until much later (1412 is her birth year, so she's likely not a Starborn, though it wouldn't shock me in the least if she was a Knight).
5. Chaucer basically decides that English is a good enough language to write in. This sounds like less of a big deal, but The Canterbury Tales in particular basically established Middle English as a legitimate literary language, which kind of shunted aside Italian, French, and Latin. Fun fact: Chaucer pretty much created 2000+ words. Shakespeare only managed about 1,700. Suck on that, Bill.
6. 1376: The Bible is translated into English. Huge, HUGE deal. John Wycliffe almost certainly did most of this himself, and it's almost 100% that he personally translated John, Mark, Luke, and Matthew, but it's possible he was responsible for translating the entire New Testament. The King James translation doesn't come for 230ish years. The main point here is that Wycliffe helped set the stage for Protestantism in the 16th century.
7. Around this time (137...8? 1379?) you have The Great Schism, and two rival Bishops both claiming to be the Pope. This lasts until somewhere around 1417, I think (I'm a medieval guy, and most of my interest ends around the Magna Carta, so someone please correct me if I'm wrong here).
8. Late, may or may not be relevant at all, but Tamerlane initiates the last Mongol Conquest in 1398ish. A Sunni Islamic culture, this was pretty much the last of the Nomadic Eurasian Steppe empires (the Timurids). For those wondering, the Empire included Iran, Afghanistan, Turkey (parts), some parts of India, Central Asia, etc.
I know it's easy to look at any century and say "Hey, this was a period of upheaval!" That said, the 1300's really WERE a period of TREMENDOUS worldwide change. The Black Death, the initial translation of the Bible, and yes, Chaucer legitimizing English as a literary language are all really, really important.
The Black Death didn't quite kill Feudalism, but it sowed the seeds of doubt among the peasantry and is often credited with helping that process along. In fact, one of the results of the Black Death was Parliament passing a LOT of laws mandating wage freezes, which helped cause a big Peasant Revolt in the 1380s (also helped that taxes kept going up to fund the Hundred Years War's various ongoing conflicts. People really hate taxes. If any of you ever become a dictator, seriously consider cutting taxes. Tax hikes usually don't end well for people in charge, while tax breaks are almost always well-received). Feudalism also ties into my ongoing William the Conqueror-was-a-Starborn-and-Hastings/Stamford-Bridge-was-the-last-time-control-of-the-Outer-Gates-changed-hands theory, since he's the one who really brought it to England with his implementation of vassalage.
Anyway, the point is that the biggest major event 666-ish years ago was the Black Death, and that really, really altered the course of Western Civilization for centuries. I don't know if a Starborn was involved, but I think it's entirely possible.
Also worth noting that Vlad Tepes's father, Vlad II Dracul, is said to be born in 1395. Since we know he's a Starborn, it's unclear exactly how close the 666-year cycle lines up; that could just be an incorrect birth year that was given because he's immortal, but it might not be. Celestial movements may not need to be precise; there may be a length of time during which Starborn can be created, and there are other things that contribute to their status at birth (I like to think there is a birth ritual involved somewhere).