Catherine II the Great

She reigned thirty-four years. The partitions of Poland turned Russia—a country where Jews had been forbidden to live—into the state with the largest Jewish population in the world: about a million people overnight. The answer was an arrangement that determined Jewish life for a hundred and twenty years: the decree of 1791 and those that followed—the Pale of Settlement, a belt of western provinces beyond which one could not move, together with double taxation and exclusion from the merchant estates of the interior cities.

It is worth saying what the usual account omits: the Pale arose not as a design for oppression but as an answer to a complaint by the Moscow merchants about competition—and only afterwards became a system.