 The French Encyclopédie, published in 1757, noted that Spanish Guyana was located between the Orinoco and Essequibo River while Dutch Guyana was located between the Essequibo River and Maroni River.Under the Anglo-Dutch Treaty of 1814, Dutch colonies of Demerara, Berbice and Essequibo were transferred to Great Britain.By this time, the Dutch had defended the territory from the British, French and Spanish for nearly two centuries, often allying with natives in the region who provided intelligence about Spanish incursions and escaped slaves.Following the establishment of Gran Colombia in 1819, territorial disputes began between Gran Colombia (later Venezuela) and the British.