Pan was the Greek God of Shepherds, Hunters & the Wilds
As the Story goes (in mythology) :
Pitys was a nymph who Pan loved.
In order to escape Pan's advances
Pitys asked the gods to transformed her into a fir tree.
Syrinx, another nymph, was turned into Reeds to escape Pan
Pan, then, used her reeds for his "Panpipes".
The Doorstop shows Pan playing these panpipes
trying to charm the nymph on the mushroom.
In the Mosaic, the Panpipes is attached to his left waist.
Pan is the only Greek god (other than Asclepius)
who according to mythology actually dies.
Mozaic from Archaeological Museum of Naples
Showing Pan & Pitys