The flag of the state of Maryland consists of the heraldic banner of George Calvert, 1st Baron Baltimore. It is the only state flag in the United States to be based on English heraldry. (While the flag of Washington, D.C., is a representation of the coat of arms of the Washington family, Washington, D.C., is not a state.) It was officially adopted by Maryland in 1904.
The black and gold design on the flag is the coat of arms of the Calvert family. It was granted to George Calvert as a reward for his storming a fortification during a battle (the vertical bars approximate the bars of the palisade). The red and white design is the coat of arms of the Crossland family, the family of Calvert's mother, and features a cross bottony. Since George Calvert's mother was an heiress, he was entitled to use both coats of arms in his banner.