John Playfair (1748 – 1819) was the Chair of Mathematics and later Philosophy at the Edinburgh University. In the early 19th century, he was also the first President of the Astronomical Institution of Edinburgh. That role earned him this monument next to the City Observatory on Calton Hill. Perhaps his equally important contribution to Edinburgh was adopting his orphaned nephew. That six-year-old child became the most influential architect in the city’s history: William Henry Playfair. He had the honor of designing this Greek Doric tribute for his uncle. It was erected in 1826.