The enigma of the Shugborough Inscription

In the grounds of Shugborough Hall in Staffordshire, England, sits an 18^th-Century monument known as the Shepherd’s Monument. The Monument contains a relief, depicting a copy of a Nicolas Poussin painting, and a cipher text that has stumped historians and decoders for hundreds of years. What is the meaning of this outwardly simple, 10-letter text? Why was it carved onto the monument? Was it a declaration of undying love, a code to locate something, or a Biblical reference? While the meaning of the Shugborough Inscription has never been verified, there have been several theories as to what it means.

The Shepherd’s Monument, which contains the enigmatic Shugborough inscription. (Wikipedia).