A January 1776 Sketch of the Flag on Prospect Hill

We have two remarks from British observers inside besieged Boston about the flag the Continentals raised on Prospect Hill in what’s now Somerville in January 1776.

Peter Force’s American Archives included a letter from the captain of a British ship to his employers in London, dated 17 January, which says:

I can see the rebels’ camp very plain, whose colors, a little while ago, were entirely red; but on the receipt of the king’s speech, which they burnt, they hoisted the union flag, which is here supposed to intimate the union of the provinces.

Richard Frothingham’s History of the Siege of Boston quoted a British officer:

Lieut. [William] Carter...was on Charlestown Heights, and says, January 26: “The king’s speech was sent by a flag to them on the 1st instant [i.e., of this month]. In a short time after they received it, they hoisted an union flag (above the continental with the thirteen stripes) at Mount Pisgah; their citadel fired thirteen guns, and gave the like number of cheers.”

Back in 2006 in the vexillogical journal Raven Peter Ansoff argued that if the “union flag” meant the British flag, then perhaps “the continental with the thirteen stripes” was a second banner flown below it.

In 2013 Byron DeLear responded in favor of the traditional understanding that the army was flying the new Continental Navy banner, including examples of “union flag” as a blanket term for many banners with a Union Jack canton.

Fortunately, we also have an image from a British officer of the flag flying over the Continental fortification. It’s dated 4 Jan 1776—the same day that Gen. George Washington wrote about the flag to his former military secretary, Joseph Reed.

That image was sketched by Lt. Archibald Robertson as part of a multi-page panorama view from his posting on Bunker’s Hill. His notebook is now owned by the New-York Public Library, which digitized those pages. Back in 2015 Boston 1775 reader Marc Shelikoff pointed out how Robertson had shown Prospect Hill.

And here is the sketch:

That’s a detail from this page.

No wonder the British in Boston thought the Continentals were ready to surrender—they were flying a white flag!

Well, not really. Obviously Robertson simply sketched the outline of the union flag that others mentioned. He was an engineer, interested in topography and fortifications rather than flag design.

But Robertson’s drawing still contributes to our understanding of the Prospect Hill flag. First of all, this strongly suggests it was a single banner, not one over another. Second, it was big! That’s probably what Washington meant when he referred to a “great Union Flag.”

TOMORROW: The Pennsylvania Packet sources.