Mercia was an Anglo-Saxon kingdom originally founded around 500 AD at its peak it covered almost all of southern England. The kingdom itself was comprised of some thirty different tribes.One of the earliest Mercian Kings of whom anything is known is Penda however probably one of the best known kings of Mercia is Offa . During part of his reign Offa made Tamworth his capital.
Mercia played an important role in the history of England for well over a hundred years.But after the death of Offa, it's importance began to decline.It suffered numerous attacks by the Danes and after 877 the kingdom was split into two some controlled by the English and some by the Danes.
In the 10^thcentury the Danish lands were re-taken by Edward the Elder. Edward was assisted in this task by his sister Aethelflaeda who was known as The Lady of the Mercians.