With the holiday season upon us, I've been seeing more and more posts on my Facebook feed such as this and this. These posts usually argue that Christmas traditions such as Christmas trees or giving gifts are derived from pagan holidays like Saturnalia or Yule, or that Christmas itself is "actually" just a renamed pagan holiday. Some posts like this one put a lot more malicious intent behind the similarities by arguing that Christians stole these holidays from the pagans and forcibly displaced it with Christmas in order to destroy their culture and holiday traditions.
So, my two questions are as follows:
How true is the argument that Christmas is a rebranded pagan holiday or that it derives many of its traditions from pagan holidays and beliefs like Saturnalia, Yule, Mithras, etc.?
How true is the argument that Christians "stole" these holidays from the pagans? Or more broadly, did they have any malicious intent in taking elements from pagan holidays for Christmas (actively trying to supplant pagan holidays, destroying their culture, etc.)?
^(Please note I've moved my account to /u/Bealoideas, so if you have any further questions on this topic, I would be happy to answer messages sent there.)
No doubt an Early Christian historian can tackle your thesis, but strictly as regards the Druids and Mistletoe, it is... well broadly incorrect as one might expect. There is a relationship between Druids and oak together with mistletoe, stemming from Pliny's Natural History, the relevant portion I will transcribe here:
Not to be overlooked is the admiration of the Gauls for this plant [the mistletoe]. The Druids - as their magicians are called - hold nothing more sacred than this plant and the tree on which it grows, as if it grew only on oaks. They choose only groves of oak and perform no rites unless a branch of that tree is present. Thus it seems that Druids are so called druid the Greek name of the oak [Greek drus]. Truly they believe that anything which grows on the tree is sent from heaven and is a sign that the tree was chosen by the god himself. However, mistletoe rather grows on oaks, but is sought with reverence and cut only on the sixth day of the moon, as it is then that the moon is powerful but not yet halfway in its course (it is by the moon they measure days, years, and their cycle of thirty years). In their language the mistletoe is called 'the healer of all'. When preparations for a sacrifice and feast beneath the trees have been made, they lead forward two white bulls with horns bound for the first time. A priest in white clothing climbs the tree and cuts the mistletoe with a golden sickle, and it is caught in a white cloak. They then sacrifice the bulls while the praying that the god will grant the gift of prosperity to those to whom he has given it. They believe that mistletoe, when taken in a drink, will restore fertility to barren animals, and is a remedy for all poisons.
One of the more famous accounts, and very influential to the present day. Not quite 'kissing under the mistletoe' however, unless your amorousness involves quite a lot of animal sacrifice.
^(John Koch and John Carey. The Celtic Heroic Age. Literary Sources for Ancient Celtic Europe and Early Ireland and Wales. Aberystwyth, Wales: Center for Advanced Welsh and Celtic Studies, 2009.)
1a) Does Christmas itself (celebrating the birth of Jesus) arise from a rebranded pagan holiday?
I'd argue strongly that this is not the case. The earliest attestation to a date for Christmas is the Chronography of 354 which also reads, "N[atalis] Invicti C[ircenses] M[issus] XXX” (“Birthday of Invictus, 30 chariot races"), often understood to be a celebration of Sol Invictus. Since neither celebration has an indisputed earlier attestation, it's no more certain that Christmas came from the Sol Invictus' celebration than the other way around.
It strikes me as somewhat unlikely that Christmas didn't emerge until the mid 4th century. The alternative argument I've seen, based on Tom Schmidt's interpretation of Hippolytus' Commentary on Daniel and Clement of Alexandria's comments, suggests that 25th Dec (" And there are those who have determined not only the year of our Lord’s birth, but also the day; and they say that it took place in the twenty-eighth year of Augustus, and in the twenty-fifth day of Pachon"). The argument is that 25th Dec is 9 months after a death date of 25th March, so that he was conceived and died on the same date.
The argument that Christians deliberately stole a holiday and Christianised it doesn't appear until the 17th and early 18th century, with proponents like Paul Ernst Jablonski and Jean Hardouin.
1b) But did they steal pagan elements?
I think this is much more likely, over the course of 2000 years, but also more difficult to establish at least in Antiquity. For example, Kelly in The Origins of Christmas (2004) notes that early Christian leaders found Saturnalian practices offensive (p69), and sought to discourage Christians from following those practices (which obviously doesn't mean that Christians didn't celebrate Saturnalia!).
Mithras is even worse off as a point of comparison. Mainly because we don't know as much about Mithraic practices as we'd like, but to all our knowledge it was a cultic mystery-type religion that was all-male, met in underground temples (well, all temples we know of are underground), and involved initiation. It was not a public and publically-celebrated type of cultus.
Kind of a follow up question. I read somewhere that after the collapse of Rome, pagans throughout Europe believed that Rome's fall was caused by the people of Rome turning their backs on their pagan gods in order to convert to Christianity. Thus, the pagan gods retaliated by turning their backs on Rome (hence the fall). The early church was aware of this and therefore accommodated to these pagans by merging their traditions with Christianity, such as branding pagan holidays as christian holidays. So, any truth to this?