Analysis of information sources in references of the Wikipedia article "Battle of Sahay" in English language version.
The imperial banner was a golden yellow cloth...bearing a black eagle...The double-headed eagle was finally established by Sigismund as regent...
The Austrian imperial standard has, on a yellow ground, the black double-headed eagle, on the breast and wings of which are imposed shields bearing the arms of the provinces of the empire . The flag is bordered all round, the border being composed of equal-sided triangles with their apices alternately inwards and outwards, those with their apices pointing inwards being alternately yellow and white, the others alternately scarlet and black