E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
used to be employed by the early Christians at Rome to decorate churches and dwellings at Christmas; it had been previously used in the great festival of the Saturnlia, which occurred at the same season of the year. The pagan Romans used to send to their friends holly-sprigs, during the Saturnalia, with wishes for their health and well-being.