[REVOLUTIONARY WAR].
BLASKOWITZ, Charles (c.1743-1823).
A Plan of the Progres of the Royal Army from their Landing at Elk Ferry to Philadelphia 1777 Under the Command of His Excellency, Sir William Howe Knight of the most Honorable Order of the Bath, Commander in Chief &ca &ca &ca Surveyed and Drawn by Order of Major General Sir William Erskine By Charles Blaskowitz Capt of the Corps Guides.
12-sheet manuscript map on paper.
[Philadelphia, 1778].
51 3/8" x 53 1/8", size from outer borders.

An extremely important manuscript map of the American Revolutionary War by one of the period's greatest surveyor-cartographers; One of only three known monumental campaign headquarters maps of the Philadelphia Campaign of 1777-8, made for General Sir William Erskine (1728-1795). Blaskowitz's map presents a highly accurate and detailed depiction of southeastern Pennsylvania and the adjacent parts of Maryland, Delaware and New Jersey. All roads and villages are illustrated with ink and watercolor. A detailed topographic projection crosses the lower half of the map moving northwards from the head of Chesapeake Bay to Philadelphia. This marks the route of the British army as it progressed against determined Continental resistance to seize the American capital in September 1777. The site of the two large field battles, Brandywine and Germantown, are illustrated, as is the siege of Fort Mifflin in the Delaware River. Daily progress is tracked, and the locations of country taverns and meeting houses are labeled, while crossed swords indicate the locations of skirmishes and red bars show the placement of brigades. It is a complete rendering of the dramatic sequence of events as they occurred from August to December 1777. The areas in the vicinity of the route of the British armies are rendered in full topographical detail, while the remainder of the map takes on the form of a road and administrative map. As indicated on the title, Blaskowitz drafted the map under the orders of Major General Sir William Erskine (1728-1795), one of the most highly-regarded commanders in the British Army. At the time it was created, it was likely the most detailed and precise map of southeastern Pennsylvania. The map is a detailed record of the British campaign to take Philadelphia, the capital of the United States, during the late summer and autumn of 1777. Operationally, it was one of the most impressive endeavors in British colonial military history, but was at the same time, a strategic failure, as it diverted the British from what should have been their true priorities.

COMPARATIVE CARTOGRAPHY: Blaskowitz's map is the only example of the three known Philadelphia campaign headquarters maps to have been made during the campaign itself. The present map was almost certainly made in Philadelphia in the early months of 1778. The map's terminus post quem is easy to discern, as the latest event inscribed on the map refers to a British "Forregeing" expedition on 22 December 1777. The terminus ante quem, would be May 1778, for the map's title identifies Sir William Howe as the commander-in-chief of the British forces, a post he vacated that month. Moreover, in June, 1778 the British evacuated Philadelphia and headed across New Jersey towards New York. The discovery of this map reveals the importance of Blaskowitz's role in the Philadelphia Campaign. Until now, the only known map by Blaskowitz of the Philadelphia Campaign is a much smaller manuscript map of the siege of Fort Mifflin. The Erskine-Blaskowitz map proves that he was very active throughout the Philadelphia venture, his efforts resulting in the finest map made in that theater. While Blaskowitz was responsible for the highly advanced survey of the route of the British army, the rest of the map is predicated on cartography from pre-war scientific surveys. A comparison to William Scull's map of Pennsylvania, originally printed in 1770, shows that it was likely used as a general template, although Blaskowitz's work is far more detailed and is of a much larger scale. Similarly, the influence of Nicholas Scull & George Heap's map of Philadelphia and its immediate environs, originally published in 1752, is evident. Scale: 1: 126,720 (2 miles to 1 inch). (3-inch semi-circular patch in upper right affecting border, some tears along edges repaired with mounting, some surface soiling).