the dutch territories of essequibo, demerara, and berbice on the north coast of south america, created in early 17th century, came under the control of the british during the napoleonic wars. these territories were formally ceded to the united kingdom in 1815 and united to become the colony of british guiana in 1831. at first, the british introduced a british variety of the dutch guilder currency into this territory. then in 1839, the spanish dollar as a unit of account was introduced in order to facilitate the introduction of british sterling silver coinage. the rationale behind this lies in the fact that spanish silver dollars, alternatively known as pieces of eight, were already circulating alongside the dutch coinage, and also widely throughout the eastern caribbean. the dollar unit of account therefore acted as a convenient intermediary conversion unit between sterling and the outgoing guilder unit. the dollar unit was equivalent to 4 shillings 2 pence sterling and replaced the guilder unit at a rate of 1 dollar = 3⅛ guilders, i.e. £1 = $4.8 = 15 guilders.