The Mercury began weekly publication on 26 September 1811, with James C. Gilleland as editor and proprietor.

[2] Within a year it was purchased by John M. Snowden, who while at the helm of the paper attained prominent local political posts, including Mayor of Pittsburgh in 1825–1828.

[2][3] In early 1830, Snowden was succeeded by his son Joseph in the conduct of the Mercury.

[9] Seeing a need for a daily Democratic newspaper in Pittsburgh, Smith in 1842 arranged with Thomas Phillips, owner-editor of a competing Democratic weekly called The American Manufacturer, to unite their establishments and launch the Daily Morning Post.

[10] The Post continued as a Democratic organ until its 1927 merger with the Gazette Times to create the Post-Gazette.