Who is Rembrandt, Raphael, Rubens, Velazquez, van Dyke from The Madonnas of Leningrad: A Novel and what is their importance?

Rembrandt, Raphael, Rubens, Velazquez, and van Dyke are some of the famous painters whose works hung in the Hermitage before the war, works evacuated from the museum for safekeeping and which are both recalled and described by Marina in great detail. Works by Rembrandt, Raphael and Rubens in particular, and most particularly their paintings of the Madonna play important roles in defining both Marina's experiences in the past and in the present, and in exploring the narrative's themes.