The purported arms of the Argyros [Argyrus] family (c. 1000), a prominent Eastern Roman family. They produced one Emperor, Romanos III, as well as other notables, including Pothos Argyros, Catepan of Italy. 
Or, a cross between four stars Azure. 

Note that the arms are not historical, but taken from the 19th-century work of Johannes Rietstap. The Byzantines did not use family emblems or western-style heraldry.
Own work (Original text: self-made, from Rietstap's Armorial [1])
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