After Napoleon's defeat, Leopold moved to the United Kingdom, where in 1816 he married Princess Charlotte of Wales, the only child of the British Prince Regent (later George IV).

As a Protestant, Leopold was considered liberal and encouraged economic modernisation, playing an important role in funding the creation of Belgium's first railway in 1835 and subsequent industrialisation.

The dynasty of this name was therefore founded by Leopold's eldest brother, Ernest I, Duke of Saxe-Coburg and Gotha, the father of Albert, Prince Consort of the United Kingdom.

The Kingdom of Prussia, which Leopold and the Russian Imperial army had fought alongside, was opposed to any gains made by the Duchy, which had been against the annexation of Saxony, an ally of France.

Emperor Alexander was also opposed to Charlotte marrying William as he believed a future personal union between Great Britain and the Netherlands would become a maritime superpower and dominate the seas.

When Charlotte again fell pregnant, she was advised by her obstetrician, Sir Richard Croft, to drastically reduce her diet, however Leopold's physician, Christian Stockmar, heavily disagreed with this advice.

[50] Following a Greek rebellion against the Ottoman Empire, Leopold was offered the throne of an independent Greece as part of the London Protocol of February 1830, which stipulated that the new monarch could not be of Great Britain, France or Russia.

With the Great Powers mainly satisfied, they signed new international protocol, officially giving Leopold, "the son-in-law of George IV", the title of "Sovereign Prince of Greece".

After a ceremony of resignation by the regent, Leopold, dressed in the uniform of a Belgian lieutenant-general, swore loyalty to the constitution, under the supervision of congressman Jean-Baptiste Nothomb, and became king.

"[78] Following the war and large losses that Belgium suffered, Leopold reorganised national defence, disbanded the Garde Civique and legislated the army's numbers at 80,000 men.

Several of the former residences of William's family in Belgium and hotels in Brussels were ransacked, leading to Leopold travelling in on horseback and convincing the protestors to disband by giving a speech.

[85][99] To appease to the public, he sought to maintain cordial relations with the Holy See, though historian Louis de Lichtervelde suggests it may have been to reassure and consolidate his own power against "the only other force [Catholicism]" that had more popularity of him.

[104] Despite this, Leopold worked closely with the government to develop infrastructure, to which he promised in his enthronement speech: "Multiple efforts will be directed towards the improvement and extension of agriculture, commerce and industry; they contribute to spreading prosperity among the various classes of inhabitants and to cementing harmony.

[111] In order to defuse tension, the government adopted multiple measured aimed at liberalising the country and preventing it from being attacked by revolutionary ideas of its neighbours.

For example, the stamp duty on newspapers was abolished and agents who the state believed could serve as potential disturbances to public order, such as Karl Marx, were expelled from Belgium in March.

[116] He organised a meeting between his father-in-law, Louis Philippe I of France, and his niece, Queen Victoria, in 1843 at the Château d'Eu, marking the first time in thirteen years that the House of Orléans received a foreign monarch.

Immediately following the 1851 French coup d'état, Leopold sent Prime Minister Henri de Brouckère to Paris to meet the new Napoleon III to assure cordial relations.

Leopold also believed that acquiring a colony would solve the issue of rising poverty rates, a cause of rapid industrialisation and food shortages following war with the Netherlands.

An exploration commission was sent on 9 November 1841 in order to finalise the purchase, however Belgian delegates soon began leaving due to unsanitary conditions, though Leopold pushed for the project to continue.

Until 1847, Belgium sent ships full of settlers, served prisoners and working-class men to the territory, promising a more hopeful future, however this failed due to harsh conditions leading to a high mortality rate.

[144] Leopold found comfort in Louise's friend and his daughter's tutor, Countess Denise d'Hulst, and he attempted to father his two sons, who began regularly rebelling against him.

[145] As his children aged, Leopold was gladdened to see his eldest son and daughter marry into the House of Habsburg-Lorraine, who served as the Emperors of Austria and previously of the Holy Roman Empire.

In 1859, he failed to convince his Cabinet to send a Belgian brigade to support Anglo-French naval troops in China, and in 1863, he played little role in negotiations concerning the purchase of the Scheldt toll.

[151] In the following months of the anniversary, Leopold and his sons visit each province of the country, where they stay at each capital and attend processions, balls, banquets, Church services and factory tours.

On 28 May, Leopold called in troops to calm the protests and angrily declared: "I will ride on horseback if necessary to protect the national representation; I will not allow the majority to be outraged; I will crush these scoundrels.

[157] Leopold was strongly against these anti-religious stances taken by Rogier's Cabinet, but remained impartial per his constitutional role as a neutral figurehead, though he did threaten to override new changes if it was made clear they were not the will of the majority.

Upon his return to Brussels in September 1860, Leopold decided to no longer preside over the Council of Ministers and to roll back on his other duties due to his aging condition.

In contrast, historian Jacques Portes has downplayed the significance of Leopold's role by painting him as an ineffective transmitter of correspondence between the two sides with little care for Belgium's impartiality.

[165] The Legion was badly defeated by republican forces at the Battle of Tacámbaro in April 1865, but was victorious in July under the command of Lieutenant Colonel Alfred van der Smissen.

On 9 December, Leopold was expected to die, however he survived the night, and he was visited by his daughter-in-law, Marie Henriette of Austria, who knelt by his side and exchanged words with him.