https://discover.familytreedna.com/groups/howell/tree?subgroups=17931

M269>L23>L51>P310>L151>P312>Z290>L21>S552>DF13>DF21>Z16267>F24434>FGC23381>BY11699>FGC23377>FTE60829>FTE82779>FTE61881 (1450CE) Migration appears to stay in England with some branches going to Ireland.

AI Overview
In the 1500s, the primary physical barrier between Wales and England was Offa’s Dyke, an 8th-century linear earthwork consisting of a large ditch and bank. Running roughly along the modern border, it served as a symbolic and practical boundary, separating the two regions. The border was also defined by natural features, specifically the River Wye and River Severn.
Wikipedia
Wikipedia
+5

Offa's Dyke: This barrier was designed to protect the Anglo-Saxon kingdom of Mercia from Welsh raids and created a clear division between the two areas.
The Welsh Marches: Before the 1535/1536 Act of Union formally fixed the border, this was an area of fluctuating control, often managed by Marcher lords.
Natural Geography: The boundary was often dictated by rivers like the Wye and the mountainous terrain.

Administrative Changes: The 1536 Act of Union officially replaced the fragmented lordship system of the Marches with new, defined county boundaries, creating a more fixed legal separation.