From its original meaning, of an Indian chief, this word came to be applied to political leaders, especially in connection with Tammany.

1

1773.  It is whispered that the Sachem has it in contemplation to go home soon, and perhaps the prorogation is to give him time to get away. [Note. Some one prominent in Massachusetts politics.]—J. Adams, ‘Works’ (1854), ix. 335. (N.E.D.)

2

1774.  The Sachems must have a Talk upon this matter—upon Them we depend to extricate us out of this fresh difficulty [as to the importation of Tea].—Boston-Gazette, March 7.

3

1805.  

        Well met, fellow freemen! let’s cheerfully greet
  The return of this day with a copious libation;
For liberty still, in her chosen retreat,
  Hails her favorite Jefferson chief of our nation—
        A chief in whose mind
        Republicans find
Wisdom, probity, honor and firmness combined.
Let our wine sparkle high while we gratefully give
The health of our Sachem, and long may he live!
First verse of a Fourth of July song: Balt. Ev. Post, July 3, p. 3/2.    

4

1817.  There is a respect due to our sachems, which this vulgar state of things diminishes. [Allusion to the ill-bred mob of visitors at the White House, after Mr. Monroe became President].—Mass. Spy, April 2.

5

1819.  This toast astounded not only their Sachem, William Mooney, but put the whole wigwam into confusion.—Id., March 10.

6