Tucked away from the hustle of downtown in Toronto’s prestige Rosedale neighbourhood, you’ll find the Integral House – easily one of the most spectacular private residences in the city. 

And after being on the market for over a year, the Integral House has officially sold for a cool $18 million. The home, which was built on the edge of a ravine at 194 Roxborough Drive, was listed in May 2019 with an asking price of $21.5-million. 

READ: Selling To The Ultra-Rich Means Telling A Good Story

Owners Mark Machin, CEO of the Canada Pension Plan Investment Board, and his wife Melissa Mowbray-D’Arbela, managing director of a large private equity firm, purchased the house for $15 million in 2016 from the estate of world-renowned mathematician and musician James Stewart, who died in 2014.

Dr. Stewart, who authored calculus textbooks that are used in universities around the world, commissioned Shim-Sutcliffe Architects to design the 17,000-square-foot house, which features an architectural design that pays tribute to the mathematical integral symbol most often used in calculus.

Perched on an east-facing cliff towards the Don Valley, the view from the house presents the hills of Chorley Park all the way down to the Evergreen Brick Works. At the centre of the house, you’ll find an intimate concert hall that seats 150 people and has served as a venue for gala performances over the years.

Stewart has said, “My books and my house are my twin legacies. If I hadn’t commissioned the house I’m not sure what I would have spent the money on.”

Glenn Lowry, director of the Museum of Modern Art, called the house “one of the most important private houses built in North America in a long time.”

Here’s a look inside the stunning 4+2 bedroom and 8 bathroom home.