Nestled among the many headstones from the 17th and 18th centuries in Stirling's Old Town Cemetery is a rather large and ornate greenhouse that surrounds three stone figures. One is that of an angel. The other two represent two sisters, one who was brutally massacred during a period of Scottish history known as the "Killing Time.

Margaret and Agnes Wilson were two teenage sisters who lived in Newton Stewart near Wigtown. They were both devout Covenanters and firm believers in the Presbyterian faith.

It was a trying time, as people were actively being forced to pledge allegiance to the king as leader of the church, rather than God. Because their strongly held beliefs clashed with this, the Wilson sisters were both tried and found guilty for refusing to pledge allegiance to King James VII. The younger sister, Agnes, was eventually freed on bail, but 18-year-old Margaret was condemned to death by drowning.

The monument in the graveyard was erected to pay homage to these martyrs. The installation occurred during the Victorian period, when society's views of cemeteries differed greatly from today's attitudes. This embellished grave marker was meant to be seen as a beautification scheme. Over time, people began to whisper that the glass enclosure was actually a barrier to prevent the spirit of the sisters from taking revenge.