One of the ways to use Historical Characters born after the PoD, Fame Equals Birth is where post-PoD Historical Characters are born, grow up to have the same personalities, and more than likely go into the same careers. Authors who believe in destiny are likely to view it as plausible, while most others consider it to be the most implausible of all five uses.
So why do it? Because it saves a hell of a lot of work.
Butterflying a Historical Character is a POD in its own right; depending on who they were, their absence can add a huge self-inflicted workload and eclipse the AH you were trying to write. (This is especially true for people whose importance is entirely offscreen: Immanuel Kant may not be a show-stealer like Napoleon, but butterfly him away and you're rewriting almost all European philosophy after 1789.)
Past a certain threshold of divergence, this loses its plausibility, at which point you're better off using ATL Twins instead - but up to that point, you can get away with a lot of recognizable names (although often only the names), especially if they're not terribly important to the plot.
A specific (and rather common) form of Convergence.
- GURPS writers, often to the detriment of the work.