The Lebedeff Family Crest was granted to the Lebedeff Family by Tsar Michael Feodorovich (the first Romanoff Tsar) in 1619.
Its formal description (in French heraldic language) is:
D'arg. à un cygne au nat., nageant sur une mer du même et tenant en son bec une couronne de laurier de sin.; au chef d'azur, ch. de la couronne impériale de Russie au nat.
In English, this would translate something like:
On a silver (white) background a swan in its natural colors, swimming on a sea of the same and holding in its beak a laurel wreath of green; on a blue chief, the emblem of the Russian Imperial crown in its natural colors.