The design of the flag is thought to have derived from the arms of the ancient Welsh ruler Gwaithfoed of Ceredigion, which depicted a black lion on a field of gold.

[1][2] The earliest source relating to the flag can be found in John Guillim's 1611 work A Display of Heraldry which described a black lion on a yellow background belonging to “Gwaythe Voyde, sometime Lord of Cardigan in Wales”.

The relationship between the black lion on a yellow field and the influential Pryse family led to a greater adoption of the flag in the surrounding area.

[5] The significance of the lion rampant regardant to Cardiganshire led to its inclusion as the sinister supporter alongside the red dragon of Wales on the coat of arms of Aberystwyth, awarded in 1961.

The yellow lion on a black field can be found flying in settlements throughout Ceredigion, and has been used by multiple establishments in the county, such as Aberystwyth Rugby Club and Ysgol Penglais School.