Cryptologic History Calendar
1806: Aaron Burr’s “Cipher Letter” to General Wilkinson, leading to charges of treason against Burr.
Summary: Burr sent a letter in cipher to General Wilkinson in New Orleans announcing he had “commenced the enterprise” and that “detachments from different points and under different pretences will rendezvous on the Ohio” River on November 1. Burr wrote that the troops (pioneer settlers) would be at Natchez in early December to meet Wilkinson. “The gods invite to glory and fortune,” Burr says. Wilkinson eliminates the beginning portion of the letter when he presents it as evidence later, and is caught doing so by Burr.