“For how many years shall this festival abide! Never shall age destroy so holy a day! While the hills of Latium remain and father Tiber, while thy Rome stands and the Capitol thou hast restored to the world, it shall continue.”
December 17th through the 23rd. The festival of Saturnalia. (Actually the celebration kept getting longer, but various emperors kept trying to reign it in.)
The poet Catullus describes Saturnalia as the best of days. It was a time of celebration, visits to friends, and gift-giving, particularly of wax candles (cerei), and earthenware figurines (sigillaria).
Trees were not brought inside, but decorated outside. But decorations were secondary to feasting, revelry, pranks and having a roaring good time.
(“Io, Saturnalia!” was the traditional greeting, like “Happy Holidays” or “Merry Christmas.”)