If you stumble around Rome enough, you'll eventually run into some old Roman customs that have, fortunately, been hung onto despite the turbulence of the past half century.
In the Handbook of Christian and Ecclesiastical Rome by M.A.R. Tuker and Hope Malleson they mention:
"...equally Roman is the sight and smell of the box leaves, called familiarly mortella, which are strewn at the entrance and up the nave and aisles of the Roman churches on festas and Stations."One of the Roman churches where you can still see this sort custom in evidence is that of the venerable basilica of San Clemente where they use bay leaves, strewn up the central aisle, on station days:
How and why this custom came about is a matter of some speculation, however it is thought to have its origins in antiquity where processions, especially triumphal one's, were frequently accompanied by fragrant leaves such as these.
Of course, this tradition also appears at other times other than stational processions in Rome. For example, traditionally on the Feast of Ss. Peter and Paul, the custom was to suspend a large basin of box leaves before the great door of the Vatican basilica. Similarly, for the papal procession of Corpus Christi, the procession was led by the gardeners of the papal palace who would spread out myrtle/mortella along the path of the procession.
Traditions such as these are well worth maintaining and/or restoring as they not only provide a rich sense of historical continuity, they also provide additional beauty and ceremony to such occasions as well as a sense of connection between creation and the ceremonial life of the Church.
