It is the Cross of St George of England with above the centre of the cross the shield of the standard arms of East Anglia, blue with three gold crowns. The arms are correctly identical to the smaller arms of Sweden, from wherever the East Anglian royal dynasty, the Wuffingas, https://soccerpennants42848.boyblogguide.com/32152921/top-guidelines-of-medieval-banners-and-flags