Gwallog ap Llênog (Welsh: [ˈɡwaɬɔɡ ap ˈɬeːnɔɡ], Old Welsh: Guallauc map Laenauc) was possibly a sixth-century ruler of Elfed, a region in the wider area...

taken hostile action against Theodric, together with Rhydderch Hen, Gwallog ap Llênog, and Morgan, all of whom are recorded as Coeling, Urien's distant...