US$5,477.77 The oldest reference to the Petrus estate comes in the early years of the 19th century, long after most Médoc estates sprang into life, and certainly lagging far behind those of nearby St Emilion, a number of which have Roman origins. The name itself refers to St Peter, who makes clear his allegiance to the estate by appearing on the label. It was during the early 20th century, particularly between the two World Wars, that Petrus broke away from the rest of the pack.