When the Ernestine lands were re-divided in 1826, Altenburg became the capital of Saxe-Altenburg, successor state to the dissolved Saxe-Hildburghausen.
Around 1830, the city walls and gates were knocked down and the old suburbia in front of the former wall were incorporated.
Industrialization began around this time and the economy and population both saw rapid growth, strengthened by the connection to the railway in 1842 (as Thuringia's first connected city).
The Revolution of 1848 led to the abdication of the conservative duke Joseph, who was replaced by his more liberal brother George.
The last duke abdicated during the Revolution of 1918 on 13 November 1918 after being promised 12 million Marks and the ownership of numerous castles.
The free-state of Saxe-Altenburg was merged with Thuringia in 1920.

Altenburg was a working-class city during the Weimar Republic, ruled by SPD and KPD, which led to heavy conflicts between left- and right-wing forces after 1933.
The Jewish community was destroyed during the Kristallnacht in 1938, many Jews emigrated or were killed in the concentration camps.
Furthermore, communists and invalids from Altenburg were murdered.
During World War II, several subcamps of the Buchenwald concentration camp were located here.
They provided 13,000 forced labourers for HASAG, the third largest German company to use concentration camp labour.
The US Army reached Altenburg on 15 April 1945 and was replaced by the Soviet Army on 1 July 1945.

In 1952, Thuringia was dissolved and replaced by  administrative divisions of East Germany (Bezirks).
Altenburg became part of the Leipzig administrative district, in which it was the second largest city.
After reunification, previously extant states were re-established in the former east Germany as federal states in the reunified Germany.
Although a majority of 54% in the district voted for Saxony in a plebiscite, the district council decided to join Thuringia together with the Schmölln district, partly because a vast majority of 80% in the neighboring Schmölln district had voted for Thuringia.
These districts had formed the eastern part of Saxe-Altenburg until 1920 and were reunified as the modern-day Altenburger Land district in 1994.
When the Ernestine lands were re-divided in 1826, Altenburg became the capital of Saxe-Altenburg, successor state to the dissolved Saxe-Hildburghausen. Around 1830, the city walls and gates were knocked down and the old suburbia in front of the former wall were incorporated. Industrialization began around this time and the economy and population both saw rapid growth, strengthened by the connection to the railway in 1842 (as Thuringia's first connected city). The Revolution of 1848 led to the abdication of the conservative duke Joseph, who was replaced by his more liberal brother George. The last duke abdicated during the Revolution of 1918 on 13 November 1918 after being promised 12 million Marks and the ownership of numerous castles. The free-state of Saxe-Altenburg was merged with Thuringia in 1920.
Altenburg was a working-class city during the Weimar Republic, ruled by SPD and KPD, which led to heavy conflicts between left- and right-wing forces after 1933. The Jewish community was destroyed during the Kristallnacht in 1938, many Jews emigrated or were killed in the concentration camps. Furthermore, communists and invalids from Altenburg were murdered. During World War II, several subcamps of the Buchenwald concentration camp were located here. They provided 13,000 forced labourers for HASAG, the third largest German company to use concentration camp labour. The US Army reached Altenburg on 15 April 1945 and was replaced by the Soviet Army on 1 July 1945.
In 1952, Thuringia was dissolved and replaced by  administrative divisions of East Germany (Bezirks). Altenburg became part of the Leipzig administrative district, in which it was the second largest city. After reunification, previously extant states were re-established in the former east Germany as federal states in the reunified Germany. Although a majority of 54% in the district voted for Saxony in a plebiscite, the district council decided to join Thuringia together with the Schmölln district, partly because a vast majority of 80% in the neighboring Schmölln district had voted for Thuringia. These districts had formed the eastern part of Saxe-Altenburg until 1920 and were reunified as the modern-day Altenburger Land district in 1994.
Altenburg