Catherine claimed that her order (I'm the only one calling it that) was set up a thousand years ago.
The present as those Canadians understand 2014, is the result of trillions of course corrections by the thousands of drones loyal to the order carrying out some generational grand plan, as well as actual time travellers blundering about like wild horses arses.
If someone doesn't invent timetravel and send a beachhead back to 1066, then of course the next thousand years are going to vanish like a fart in a sauna.
Although because of branch theory, if you go back far enough, the splayed multiverses billion, by billion will conjoin back into a single universe, which is possibly it's naked state before Timetravel started messing things up.
But if in the 23rd century (just a guess) when Catherine's order is launched (totally a guess. Nothing to back it up.) a thousand years in the past, if every timeline, all infinite of them, each sends back a mission to the 11th century, that would mean that an infinite number of orders are going to be set up in the same point in space time on top of one another, which would destroy the universe by drowning it in too many people to fit comfortably.
Bugger.
This show still doesn't have enough cemented rules to lock down what is happening.