In 764 King Eanmund of Kent died and was
replaced by two joint kings: Heabert and Egbert II.
Offa himself travelled down to Canterbury in
764 to attend the coronations. The method by which the people of Kent chose a
new king is not entirely clear, but it seems to have been the nobles who had
the right to appoint a new ruler, though they had to choose an adult man from
among the ranks of the ruling dynasty, the Eskings. Kent had seen joint kings
before, there being a long standing division between east Kent and west Kent,
with the River Medway marking the boundary. Usually one of the joint kings was
the acknowledged senior with the junior ruler concentrating on his own lands
and steering clear of international or church matters.
A coin
of Offa showing him in armour, but bareheaded. The inscription describes him as
"Rex Mercior" or King of Mercia.
There is some evidence that it was Offa who
had chosen the new joint kings. It may be that he came to Kent not to attend
the celebrations but to ensure that his placemen got chosen.
While he was there, Offa chose to demonstrate
his overlordship of Kent in a very solid fashion. King Heabert granted some
land to the Bishop of Rochester. It was usual when this happened for the title
deeds, or charter, to be signed by the ruling King and witnessed by whichever
nobles and clerics were around at the time and had learned to read and write
well enough to sign their names and, hopefully, have read the charter. This
particular charter, however, was signed not by Heabert, but by Offa. Heabert
signed as a mere witness among others though he did describe himself as King of
Kent when he did so. One name noticeably absent was that of the new King Egbert
II.
When Egbert did choose to act he did so on his
own account. Some months after Offa had gone back to Mercia, Egbert chose to
have a charter confirmed by King Heabert, implying that it was Heabert who was
the senior ruler. Offa's name is nowhere to be seen. One name that does appear
as a witness is that of Jaenbert, Abbot of St Augustine's Abbey in Canterbury.
The following year Bregowine, Archbishop of Canterbury, died and Jaenbert was
elected to succeed him. A few months later Heabert died and Egbert II became sole
King of Kent.
All appeared calm, with Offa clearly having
the upper hand over Kent. But ten years later he overstepped the mark. In 774
Offa called a meeting of Mercian churchmen and Archbishop Jaenbert went along
to officiate as was his right. Travelling with Jaenbert was a nobleman named
Baban, who may have been acting as observer for Egbert II or who may have been
there on his own business.
At the meeting Offa decided to give some land
he owned to the Archbishopric of Canterbury. Jaenbert was, naturally, pleased but
Baban was not. Although the land belonged to Offa the taxes on it were owed to
Egbert II and so Offa should have asked Egbert for permission to transfer the
land. He did not, he simply signed the charter and when Baban objected told him
that Egbert would have to accept the situation.
When the news reached Egbert he was
predictably furious. Offa had acted as if he, not Egbert, were King of Kent.
Having an overlord living miles away in Mercia was one thing. Having an
overlord who issued orders to you, expected to have them obeyed and then
insulted your dignity was something quite different.
It was not only Egbert who was enraged, the
Kentish nobles were incensed as well. Egbert was from their own royal family,
was related to many of them and had been chosen by them. Offa was a foreigner
with no links to Kent at all. While they could expect to have some influence
over a local king, they could have none over Offa. Jaenbert was also
unimpressed. It suited the Archbishops of Canterbury to be ruled by a local
king who could be influenced by them rather than to have a powerful but remote
monarch.
In 775 Egbert threw off Offa's overlordship.
He began ruling in his own right, making no reference to Offa and not seeking
to have new laws or taxes approved by his supposed overlord. In his turn Offa
could not afford to let this rebellion, as he saw it, go unpunished. He
gathered an army and in 776 sent it south to invade Kent.