London: Printed for W. Strahan; and T. Cadell, 1776-1788. Rare full first edition set, first state of volume one, of Gibbon's landmark work of historiography with three engraved folding maps by Kitchin of the Western and Eastern Roman Empire and of Constantinople and frontispiece portrait of Gibbon. Quarto, 6 volumes bound in three quarter calf over marbled boards with gilt titles and tooling to the spine. Vol. I: undated engraved portrait frontispiece by Hall after Joshua Reynolds, 12pp. contents, x4 and a4 are cancels, errata leaf; Vol. II: full-sheet folding map of the Eastern Roman Empire by Thomas Kitchin dated 1 January 1781 bound before p.1, half-sheet map of Constantinople and environs by Thomas Kitchin dated 1 January 1781 bound before p.22., G1 and Ll1 are cancels, errata leaf; Vol. III: full-sheet folding map of the Western Roman Empire by Thomas Kitchin dated 1 January 1781 before p.1, p.177 correctly numbered, p.179 line 18 reading "Honorious," errata leaf; Vol. IV: H3…