In 1859 a treaty officially established the boundaries of Belize.
In 1940 Guatemala declared the Treaty to be void, alleging failure to implement article 7 (That the British build a road which they never did) A new Guatemalan Constitution in 1945 declared Belize to be Guatemalan territory
Belizean culture and nationality developed throughout the 19th century (and the British became the minority). Self-government was achieved in 1964, but full independence was delayed until 1981 only because of the Guatemalan claim to the territory.
Guatemala changed its argument in 1999. it rested its case on the 18th century Treaties between Britain and Spain covering the area between the Hondo and the Sibun Rivers. Guatemala claimed that the area between the Sibun River and the Sarstoon River was 'illegally' occupied by Britain, and argued that the area south of Sibun up to the Sarstoon River must be "returned" to Guatemala together with all the cayes which were not included in those Treaties. The area thus claimed by Guatemala amounts to over 12,000 square kilometres, which is more than half of Belize's territory. The British occupied this territory when it was uninhabited and unsettled.
Belize rests its case on two firm pillars: the right of a people to self- determination and the fact that Guatemala's claim is legally untenable.
Negotiations began between Britain and Guatemala and Belize....