I went to New Edinburgh and Rideau Hall on Thanksgiving Day in October to take in some of the fall colours. I happened to arrive in time to join a tour inside the Hall, which is home and working space for Canada's Governor-General. Usually the tour begins through the front door, but with the work going on there, the tours were being started at an alternate entrance, through one of the working corridors of the building.
The tour properly began in what's called the Tent Room. This is a large reception space with paintings of Queen Victoria and numerous governor-generals of British origin adorning the walls. The concept of the governor-general goes all the way back to the New France era, in which governors were appointed to oversee French holdings in North America. After the Seven Years War ended with the British taking full control of those territories, the idea of the governor continued on in the form of a governor-general. These days it's a largely ceremonial position, a representative of the Queen, who continues to be monarch of Canada.
As for why it's called the Tent Room, British representatives in the 19th century had a fondness for tent garden parties. This space was created with that in mind- an interior space as opposed to an outdoor space, since winters in Ottawa don't make for ideal conditions for outdoor entertaining. It was also used as an indoor tennis court.
In an adjoining room, the space is given over to an explanation of various Canadian honours- including the Order Of Canada, of which this is an example.