market town, Vale of Glamorgan county, historic county of Glamorgan (Morgannwg), Wales. Centrally located in the Vale of Glamorgan, Cowbridge dates from the 14th century and prospered as the chief market and population centre of the area. The town may have been the site of the Roman military station Bovium, as evidenced by its rectangular layout and the discovery of Roman coins nearby. To the east is the traditional site of the Welsh leader Owen Glendower (Glendower, Owen)'s victory over Henry IV in 1405. The commerce of the 19th century placed an increased economic emphasis on ports, and since then Cowbridge has been almost completely overshadowed by the nearby ports of Barry and Cardiff. Pop. (2001) with Llanblethian, 4,182.