A discussion from the Sean Styles Radio Merseyside show about West Derby Castle and Merseyside in the Domesday book. For more information, read: www.historyofliverpool.com/li...
Mersey originates from the ancient border between Mercia (with Norwegian Vikings settling on Wirral, Cheshire & South, the Mercian Army Regiment today is based in Chester), and Northumberland (Under Danelaw, from Danish Viking 'settlers'), now Lancashire. Liverpool owes its origins from the 6 Monks of Birkenhead Priory, operating the first Mersey Ferries for taxation to the crown of England (still operating under a royal charter), from Monks Ferry (Woodside), in Birkenhead to the 'Pool of Liver'. Liverpool logically owes it's very existence to those Monks, developing a hundred years or more, later.
To this day when you are looking for ancestors, you look for people in West Derby not Liverpool. On the Wirral, people from Wallasey were Welsh, it was an island inhabited by the British, Wirral was almost impossible to move around, all the old villages were on hills surrounded by marsh.
It's more believable to me knowing kirche is German for church and he says bi meant a place, Kirby the place of the church confirmed, fascinating stuff.