It's the Cross of St George of England with more than the centre of the cross the defend of the standard arms of East Anglia, blue with 3 gold crowns. The arms are proficiently similar to the tiny arms of Sweden, from wherever the East Anglian royal dynasty, the Wuffingas, https://medieval-banner-flag35789.educationalimpactblog.com/54864901/indicators-on-medieval-flag-maker-you-should-know