Flag of the Prussian Commonwealth, Anglo-Iberian timeline.
This flag has been used since 1904, after the new borders of Prussia were consolidated. Compared with the previous flag, the two golden stripes were added to represent victory and new wealth, and the wings of the eagle were shown spread rather than folded, reminiscent of the Prussian War Flag used throughout the Great War, again representing victory and showing Prussia's prowess and dominance in north-central Europe as a military power.
Prussia lost much of it's global territories during the Great War, including - most devestatingly - most of Japan, which had been conquered earlier in the previous century. Even so, Prussia is still a dominant and major European power, and the Commonwealth includes territories in East Africa, Indochina, and the city-states of Aden in Arabia and Wilhelmburg in Australia.