Archduke John of Austria (German: Erzherzog Johann Baptist Joseph Fabian Sebastian von Österreich, IPA: [ˈɛʁt͡sˌheʁt͡sok ˈjoːhan]; Slovene: Nadvojvoda Janez Habsburško-Lotarinški (or simply Nadvojvoda Janez); 20 January 1782 – 11 May 1859), a member of the House of Habsburg-Lorraine, was an Austrian field marshal and imperial regent (Reichsverweser) of the short-lived German Empire during the Revolutions of 1848.

John was born in Florence, the thirteenth child of the Habsburg Grand Duke Leopold I of Tuscany (Archduke of Austria and later Emperor) and Maria Louisa of Spain.

In 1790, Leopold succeeded his brother Joseph II as the Holy Roman Emperor and his family moved from the Grand Duchy of Tuscany to the Imperial court in Vienna.

Educated by the Swiss historian Johannes von Müller, he developed wide-ranging skills and interests, especially in the history and geography of the Alpine countries.

After the Peace of Lunéville in 1801, Archduke John was made General Director of the Engineering and Fortification Service, and later commander of the Theresian Military Academy in Wiener Neustadt.

John remained obliged to Tyrol and maintained friendly contact with Baron Joseph Hormayr who forged a resistance movement against the Bavarian occupation.

Ordered to join his brother Archduke Charles at the Battle of Wagram on 5 and 6 July, John's small army arrived too late to avert an Austrian defeat.

In his early days Archduke John and his brother Louis had the habit of travelling to France, where the latter married Madame de Gueroust.

His proximity to the people is given evidence to by his many contacts with the common man, by wearing the local Tracht, the Steireranzug, and by collecting and promoting the material and spiritual culture of the country.

The inheritance of his maternal uncle Albert Casimir, Duke of Teschen enabled him to acquire a tin factory in Krems near Voitsberg and coal mines near Köflach, thereby he also became an industrialist.

There, Frederick William toasted all of the guests who had fought in the Napoleonic War, including Archduke John, "whose name exhilarates us as a fresh breeze from the mountains.

Based on his reputation among the masses as a liberal and his personal character as a loyal prince of the reigning House, Archduke John was appointed on 16 June to be an effective viceroy in the absence of the emperor.

On a proposal by the liberal politician Heinrich von Gagern, the assembly on 28 June 1848 voted for the establishment of a central authority (Provisorische Zentralgewalt) and on the next day a broad majority elected Archduke John regent of the realm (Reichsverweser).

The whole Austrian Ministerial Council demanded action, and, as a result, the Archduke was forced to dispatch a formal complaint as Viceroy of Austria to himself as Regent of Germany.

Minister Anton von Schmerling acted as head of government, until from November 1848 the cabinet gradually lost the support of the centrist Casino faction and finally its majority in parliament.

Schmerling was forced to resign and on 17 December, Archduke John had to appoint Heinrich von Gagern new minister president, though he opposed his 'Lesser German' ideas.

By the terms of his Regency, Archduke John was forbidden to take part in the drafting of the Frankfurt Constitution, which was adopted on 28 March 1849 after lengthy negotiations led by Gagern.

He inveighed against the strong position of Prussia and was determined to resign, but he was once again dissuaded by appeals from National Assembly President, Eduard von Simson.

When in April 1849, King Frederick William IV of Prussia disappointed Gagern's hopes and openly rejected the Constitution, Archduke John remained passive and reminded his Prime Minister of the terms of his service as Regent, forbidding his interference in the process.

Prussia exerted pressure on the Regent to vacate the office that he had resigned, but the Archduke insisted that he would remain out of a sense of obligation, and had powerful backing from Austria's Prime Minister, Prince Schwarzenberg, who was eager to stifle Prussian ambitions in Germany.