To expand on the matter, what had happened was that around the end of WWII, the Progressive Party and the Conservative Party were both in dire electoral straits, to the point where the Conservatives couldn't even get anyone to be the party leader. So they asked the leader of the Progressive Party to be their leader and merge the two parties; he agreed on the condition that the parties' names be merged as well. Hence, the Progressive Conservative Party.
Much later, in the 1988 election, a protest party, the Reform Party, ran candidates in Western Canada. They didn't win any seats, but they did pick up a by-election later in that Parliament. In 1993 they completely supplanted the Progressive Conservatives in the West. Between the 1997 and 2000 elections the Reform Party changed its name to the Canadian Alliance in an attempt to lure PC MPs to them; it didn't really work and after the 2000 election the parties merged outright to form the Conservative Party (originally the Conservative Reform Alliance Party, and they've lived up to the acronym). This made some MPs jump ship to the Liberal Party, while a few others sat as independents for the remainder of that Parliament.
As I recall, the Progressive Conservatives liked to bill themselves as "fiscally conservative, socially progressive".
