During my western civilization class today, my instructor told the class that there was a discrepancy in how European civilizations kept the date and the year could either be in the 1800's or 2200's. According to him, when the collapse of the Roman Empire occurred, western civilization lost the cohesiveness to keep a calender synced. I have never heard of this, though I have heard of the phantom time hypothesis. Is there any veracity in his statement?
No. This is a ridiculous theory which, like the Phantom Time Hypothesis, would imply that no other place, like, say, China, in the world was capable of telling or keeping time. I am frankly shocked and appalled that anyone put in front of a class would spout such nonsense.
Radiocarbon dating, archaeology, astronomy and dendrochronolgy (dating by tree rings) are very helpful, accurate methods used to confirm our assumptions about the historical record. Among other means, historians also use methods of text analysis, including claimed authorship, linguistic analysis, script analysis (paleography) and secondary testimony (including corroborating artifacts).
Where did your teacher get this idea from? The internet needs to know.
My guess: either your teacher is mistaken (too many conspiracy theories and popular history?) or they were trying to see how many of you were awake.
Your teacher is clueless. We have astronomical observations from ancient times from around the world which can be precisely dated due to the predictability of certain astronomical phenomenon such as eclipses. Moreover, these and other observations link Chinese and Japanese records, which were continuous through the middle ages, with various events in Europe before and after the middle ages. There simply is no possibility for such a gap.