Vexin is in France.
On 27th August 1172 Henry the Young King [aged 17] and Margaret Capet [aged 15] were married at Winchester Cathedral [Map]. Margaret's dowry included the Vexin; the border between France and Normandy. On the same day they were both crowned by Archbishop Rotrou. She the daughter of Louis VII King of the Franks [aged 52] and Constance of Castile Queen of the Franks. He the son of King Henry "Curtmantle" II of England [aged 39] and Eleanor of Aquitaine Queen Consort Franks and England [aged 50]. They were half fourth cousins.
In July 1087 King William "Conqueror" I of England [aged 59] injured at Mantes.