"They'd spread pretty far out by the later era," Koschei said, frowning. "But we're not allowed to go that far back, not to the end of the universe. Too dangerous, too unpredictable. It's next to impossible to know when a sun in going to die."
"And I'm from Gallifrey," Koschei said. "Time Lord. But I suppose if you've met my poor excuse for a doppleganger, then you know that."