"He felt he was preparing them for the future; they might need such verses later in life. His own biography provided a stirring example of the virtues of mental husbandry. He’d been grateful for every scrap of poetry he had in his head during his enforced exile in the Arctic, banished there by a Soviet government that did not know what to do with his genius and that, in a symbolic embrace of a national policy of brain drain, expelled him from the country in 1972."
From "Why We Should Memorize," by Brad Leithauser.
(In 1972, Brodsky became the poet in residence at the University of Michigan. I was a student there at the time and remember a grand assembly with Brodsky received as a great hero.)