The claim about Juvenalia is usually that it was the Roman solstice or early January holiday where the celebration of the youth, singing carols, and gift giving came from. Claims like this are usually made by people who watched the History Channel’s programs and their views of Juvenalia:
“Also around the time of the winter solstice, Romans observed Juvenalia, a feast honoring the children of Rome.” HC
Juvenalia was actually instituted in A.D. 59 by Emperor Nero to celebrate his first shave at the age of 21.
In other words, he was no longer a child, but an adult. Juvenalia was not a celebration of youth, but of coming out of adolescence to be a real man.
In this article I am listing sources instead of copying the quotes because they are long, but please don’t gloss over what the source says. Go to it and read it. Read each of them.
We can go back to Tacitus (AD 56 – 117), the earliest historian who recorded the invention of Juvenalia. Tacitus was 2 or 3 years old when Nero celebrated his Juvenalia.
Tacitus records Nero’s creation of Juvenalia in his Annales, XIV.15-16 [English/Latin Parallel] XV.33 [English/Latin Parallel] XVI.21 [English/Latin Parallel]
Again, no particular date, nothing about a childhood celebration or gift giving. Nero did command his people to sing or perform lewd songs and acts in the theaters he had constructed for this occasion.
Next is Suetonius (c. AD 69 – c. 122) [roughly contemporary with Tacitus], who wrote in his The Lives of the Twelve Caesars, [English/Latin] but gives only a very brief account, stating nothing about the date of Nero’s beard shaving party, nor about any child’s gathering or gift giving.
Born almost 100 years after the Nero invented Juvenalia, Cassius Dio (AD c. 150 – 235) gives a description that is more detailed than that of Tacitus or Seutonius in his Roman History 62.19-21 [Greek Text][English Text] Found in Vol. VIII of the Loeb Classical Library edition, 1925 LXI:19-21, pp. 77-82.
No date for Nero’s Juvenalia is mentioned by Cassius Dio. He does mention that Nero had theaters constructed for the event. He also mentions that Nero forced people from the high end of society in to humiliating and lewd acts in honor of the emperor’s first shave, which they did because they had a not unreasonable fear that Nero would kill them if they displeased him.
Dio also writes that Domitian (AD 51 – 96, emperor from 81-96)gave Juvenalia games but assigns no date.
So, now we are 175 years after Nero instituted Juvenalia, and we have no date of the year, no mention that this festival is for the good of children, and no mention of gift giving. We do have the fact that Nero constructed theaters for this celebration and commanded performances that included a singing competition. And, of course, Nero was declared the best singer of all.
The choice of December 25th and January 6th for the Christmas observance is already established by the end of the 2nd century AD.
via Steadfast Lutherans » Redeeming Holy Days from Pagan Lies — Pagan Solstice Celebrations 2.