[[File:Gwynedd after the Treaty of Aberconwy
1277.svg|right|thumb|250px|Gwynedd after the Treaty of Aberconwy
Treaty of Aberconwy was signed in 1277 by King
Edward I of England and Llewelyn the Last of modern-day Wales, who had
fought each other on and off for years over control of the Welsh
The treaty granted peace between the two, but
also essentially guaranteed that Welsh self-rule would end upon
Llewelyn, wanting to cement his links to royalty more forcefully,
sought to marry Eleanor de
, daughter of Simon de Montfort
and King Edward's cousin. They were married by proxy in 1275, but when
Eleanor sailed from France to meet
Llewelyn, Edward hired pirates to seize her
ship; she was imprisoned at Windsor Castle.
Edward, who was newly acceded to the throne of England, viewed
Llewelyn as a threat, and particularly disliked the idea of his
marrying the daughter of de Montfort, who had been the biggest
threat to his royal predecessor's reign. Edward also summoned
Llewelyn to appear before him on several occasions, which Llewelyn
refused on the grounds that he was not safe at Edward's
In 1276, Edward declared Llewelyn a rebel and gathered an enormous
army to march against him. By the summer of 1277, Edward's forces had
reached the heart of Gwynedd. Edward's men confiscated the harvest in
deprived Llewelyn and his men of food, forcing Llewelyn to
resulted was the treaty of Aberconwy, which guaranteed peace in
Gwynedd in return for several difficult concessions from Llewelyn,
including confining his authority to lands west of the River Conwy, while lands east were granted to his brother
Dafydd ap Gruffydd, with whom he
had earlier fought for control of Wales.
Llewelyn was not
stripped of his recently-proclaimed title, Prince of Wales — but
most of the lesser Welsh rulers who had paid him fealty
were no longer to recognize him as their lord.
signed, Edward began building several fortresses along the approach
to Gwynedd, at Aberystwyth, Builth, Flint and Rhuddlan.
In the years after the treaty, Llewelyn sought to consolidate what
power he had left. He paid homage and tribute to Edward, who agreed
to allow Llewelyn's marriage to go forward. In 1278, Llewelyn and
Eleanor de Montfort were married in Worcester Cathedral, with Edward present at the nuptials.