[1] There are two rival designs for the flag which are both based on historic armorial devices.

One concept for the flag is a banner of the arms of Brochwel Ysgithrog, famed for his resistance to the invading Saxons.

In the medieval period a coat of arms was created for him bearing three white horse heads on a black field.

In 1573 the Lordship was transformed into the County of Montgomeryshire by the Laws in Wales Acts however there is compelling evidence that the shire continued to be popularly represented by the banner of arms of Powys because a book published in 1894 illustrates the shields of the counties of Wales and shows Montgomeryshire using a red lion device and the motto 'POWYS PARADWYS CYMRU'.

[4] This design however suffers from the fact that it may be too similar to the existing flag used for the English county of Somerset.