The Letter below is an example of an American letter of marque that was issued in the War of 1812 to Captain of the Prince of Neufchatel, comprising 18 guns and 129 men, by James Madison, President of the United States of America. This letter is archived in the Public Record Office in Richmond, Surrey in the UK (High Court of Admiralty HCA32/1342).

Letter of Marque carried by Captain Millin of the American privateer Prince of Neufchatel during the War of 1812.
James Madison, President of the United States of America,
To all who shall see these presents, Greeting:

BE IT KNOWN, That in pursuance of an act of congress, passed on the 26th day of June one thousand eight hundred and twelve, I have Commissioned, and by these presents do commission, the private armed Brig called the Prince Neufchatel of the burden of three hundred & Nineteen tons, or thereabouts, owned by John Ordronaux & Peter E. Trevall of the City & State of New York and Joseph Beylle of Philadelphia in the State of Pennsylvania Mounting eighteen carriage guns, and navigated by one hundred & twenty nine men, hereby authorizing Nicholas Millin captain, and William Stetson lieutenant of the said Brig and the other officers and crew thereof, to subdue, seize, and take any armed or unarmed British vessel, public or private, which shall be found within the jurisdictional limits of the United States, or elsewhere on the high seas, or within the waters of the British dominions, and such captured vessel, with her apparel, guns, and appertenances, and the goods or effects which shall be found on board the same, together with all the british persons and others who shall be found acting on board, to bring within some port of the United States; and also to retake any vessel, goods, and effects of the people of the United States, which may have been captured by any British armed vessel, in order that proceedings may be had concerning such capture or recapture in due form of law, and as to right and justice shall appertain. The said Nicholas Millin is further authorized to detain, seize, and take all vessels and effects, to whomsoever belonging, which shall be liabel thereto according to the law of nations and the rights of the United States as a power at war, and to bring the same within some port of the United States, in order that due proceedings may be had thereon. This commission to continue in force during the pleasure of the president of the United States for the time being.

GIVEN under my hand and seal of the United States of America, at the City of Washington, the twelfth day of December in the year of our Lord, one thousand eight hundred and fourteen and of the independence of the said states the thirty ninth.

BY THE PRESIDENT James Madison
Jas. Monroe, Secretary of State.