The dictionary defines an effigy as a representation of a specific person in the form of a three-dimensional sculpture. In modern times the effigy is often seen in the form of a photograph printed on porcelain and embedded into the headstone.
However; before this medium was available, images of the dead were carved into stone in the form of a medallion (a circular device bearing a portrait or relief moulding). Symbolic of the soul, it was a perpetual remembrance of the departed.
I shall be satisfied when awake with thy likeness.
Here Damon lies, whose songs did sometime grace
The murmuring Esk, may roses shade the place. Words from a sonnet by Chaucer
How bright these glorious spirits shine
How treasured are the memories of the past
The love that we shared is everlasting and true
Together we find strength in sweet memories of you.