Arms of alliance refers to the heraldic practice of displaying two armorial bearings in their own right side by side, as opposed to impalement or dimidiation. Arms of alliance are acquired either by marriage or taken up by the children of heiresses to show their maternal descent.^[1][2][3] Arms of alliance are used almost exclusively by royalty and the nobility, while commoners typically impale the arms of both parties within a single shield.^{[citation needed]}