Alabama: Polity Style: 1817-1819

15 Aug 1817	part of the Mississippi Territory is constituted as a separate territory of the United States under the name of Alabama in accordance with an act passed by the Congress of the United States (Senate on 21 Feb 1817, House of Representatives on 3 Mar 1817), signed into law 3 Mar 1817, and taking effect on the date (15 Aug 1817) prescribed by Sec. 5 of the said act (Statutes at Large, 3:371-373) [1][2]
15 Aug 1817 - 14 Dec 1819	Alabama Territory
2 Mar 1819	the Alabama Territory is authorized to form a constitution for further admission to the Union in accordance with an act passed by the Congress of the United States (Senate on 12 Jan 1819, House of Representatives on 17 Feb 1819, amendments are concurred in by the Senate on 23 Feb 1819), signed into law 2 Mar 1819 (Statutes at Large, 3:489-492) [3]
14 Dec 1819	the Constitution of the State of Alabama, adopted by the Constitutional Convention of the Alabama Territory on 30 Jul 1819 and signed on 2 Aug 1819, is approved and Alabama is admitted to the United States under the name of the State of Alabama in accordance with a resolution of the Congress of the United States (passed by the Senate and House of Representatives on 8 Dec 1819, approved by the President of the United States on 14 Dec 1819) (Alabama Convention 1819, pp. 37-39; Statutes at Large, 3:608)

Full title: An Act to Establish a Separate Territorial Government for the Eastern Part of the Mississippi Territory.
The act took effect on 15 Aug 1817 when the Constitutional Convention of Mississippi approved a constitution and state government.
Full title: An act to enable the people of the Alabama Territory to form a Constitution and State government, and for the admission of such state into the Union on an equal footing with the original States.