Lore:
Chapter 1: Alexandru Ioan Cuza and his reforms 
Thus Cuza achieved a de facto union of the two principalities. The Powers backtracked, with Napoleon III of France remaining supportive, while the Austrian ministry withheld approval of such a union at the Congress of Paris (18 October 1858); partly as a consequence, Cuza's authority was not recognized by his nominal suzerain, Abdülaziz, the Sultan of the Ottoman Empire, until 23 December 1861. Even then, the union was only accepted for the duration of Cuza's rule.
The union was formally declared three years later, on 5 February 1862, (24 January Julian), the new country bearing the name of Romania, with Bucharest as its capital city.
Cuza invested his diplomatic actions in gaining further concessions from the Powers: the sultan's assent to a single unified parliamentand cabinet for Cuza's lifetime, in recognition of the complexity of the task. Thus, he was regarded as the political embodiment of a unified Romania.
Assisted by his councilor Mihail Kogălniceanu, an intellectual leader of the 1848 revolution, Cuza initiated a series of reforms that contributed to the modernization of Romanian society and of state structures.
His first measure addressed a need for increasing the land resources and revenues available to the state, by nationalizing monastic estates in 1863. Probably more than a quarter of Romania's farmland was controlled by untaxed Eastern Orthodox "Dedicatedmonasteries", which supported Greek and other foreign monks in shrines such as Mount Athos and Jerusalem, presenting a substantial drain on state revenues. Cuza got his parliament's backing to expropriate these lands.
During the secularization of the Antiochian Metochion in Bucharest, Cuza exiled its proistamenos the Metropolitan Ioannikios of Palmyra and arrested its hegumen Seraphim, later Metropolitan of Irenopolis in Isauria. He offered compensation to the Greek Orthodox Church, but Sophronius III, the Patriarch of Constantinople, refused to negotiate; after several years, the Romanian government withdrew its offer and no compensation was ever paid. State revenues thereby increased without adding any domestic tax burden. The land reform, liberating peasants from the last corvées, freeing their movements and redistributing some land (1864), was less successful.
In attempting to create a solid support base among the peasants, Cuza soon found himself in conflict with the group of Conservatives. A liberal bill granting peasants title to the land they worked was defeated. Then the Conservatives responded with a bill that ended all peasant dues and responsibilities, but gave landlords title to all the land. Cuza vetoed it, then held a plebiscite to alter the Paris Convention (the virtual constitution), in the manner of Napoleon III.

Chapter 2: the coup

On the night of the 11th of February 1866, two military officers, Nicolae Haralambie and Dimitrie Lecca break into Alexandru Ioan Cuza’s room.
They threatened him with his killing if he didn’t abdicate , so naturally , he did.
The provisional government was formed , all of his conspirators being part of it, it was called “the monstrous coalition”:
Gheorghe Grigore Cantacuzino , Nicolae Grigorescu , Dimitrie Lecca, Lascăr Catargiu , Ion C. Brătianu , C.A Rossetti , Ion Ghyka, Nicolae Grigore Racoviță ,Petre Marogheorghenii , Dimitrie Sturdza and Grigore Sturdza. 
This government was chaotic , the noblemen’s political views varying from Conservatives to Staunch Liberals , but they all had something in common, they hated Cuza and his reforms.

Chapter 3: the new ruler “domnitor”

After the successful coup , the provisional government sent Ion Brătianu  and Ioan Bălăceanu  to Paris , their mission was to find a foreign monarch to replace Alexandru Ioan Cuza. 
The  3 contenders were:
-Phillip of Flanders
-Karl Eitel Friedrich Von Hohenzollern-Sigmaringen 
-Leopold Stephan Karl Von Hohenzollern-Sigmaringen.

Phillip of Flanders refused due to Napoleon III’s opinion

Karl was cut out of the option because he wasn’t married , didn’t have an heir and was an absolutist , which is something Cuza was.

The last option was Leopold , and so Leopold was chosen to be “domnitor” of the United principalities of Romania.
The last things were the following:
For Kaiser  Wilhelm I to accept the proposal
For the plebiscite vote 
For Leopold to agree.

Finally , all were agreed.
On the 10th of may 1866, the new “domnitor” arrived in Romania along with his family: Infanta Antonia of Portugal, and his son, Ferdinand I , the future unifier of the kingdom. 

Chapter 4: the modernization of Romania and the abolition of the provisional   government.

The new king was sent to Bucharest , a city stuck in the 17th century , it looked more like a big village more than anything. 
Leopold I first settled as “domnitor” forming a new parliament and abolishing “the monstrous coalition”.
Two  new parties were formed:
PNL (formed earlier in this timeline)
Founding Members of PNL were:
Ion C. Brătianu  and Ion Ghica 
The Conservative Party 

In 1867, the first constitution was adopted.
Constitution:
The Fundamental Law of the United Principalities of Romania (1867)

Preamble:
In the name of the Almighty, We, Leopold I, by the Will of the People and the Grace of God, Prince of Romania, together with the Representatives of the Nation in Parliament assembled, seeking to consolidate the national unity, ensure the rule of law, guarantee public liberties, and secure the prosperity of the Fatherland, do hereby decree and establish this Fundamental Law for the United Principalities of Romania.

Title I: The Prince, The Throne, and The Dynasty

· Article 1: The form of government of the United Principalities is a Constitutional Monarchy, under the hereditary and constitutional authority of Prince Leopold I of Hohenzollern-Sigmaringen and his legitimate descendants, according to the rule of primogeniture and male-preference cognatic primogeniture.
· Article 2: The person of the Prince is inviolable. His ministers are responsible.
· Article 3: The Prince attains his majority at the age of 18. Upon accession, he takes an oath before a joint session of Parliament to "faithfully observe the Fundamental Law and the laws of the Nation, to maintain the national rights and the integrity of the territory."
· Article 4: (The Heir Clause) The stability of the Throne is hereby secured through the clear line of succession. The heir apparent shall bear the title of Crown Prince of Romania.
· Article 5: The Prince holds the supreme command of the armed forces, declares war and concludes peace, with the subsequent approval of Parliament. He accredits and receives ambassadors.

Title II: The Rights and Liberties of Romanians

· Article 6: Romanians are equal before the law, regardless of social class or religious creed.
· Article 7: Individual liberty is guaranteed. No one can be persecuted except in the cases and in the forms provided by law.
· Article 8: Freedom of conscience is absolute; freedom of all religious worships is guaranteed.
· Article 9: Freedom of the press and freedom of assembly are guaranteed, within the limits of the law.
· Article 10: (The Cuza Clause) Property is inviolable. The land reforms enacted by the state are recognized as lawful and concluded. No further universal, non-compensated confiscation of property shall be enacted, ensuring the security of both the new smallholders and the remaining estates.

Title III: The Legislative Power

· Article 11: Legislative power is exercised collectively by the Prince and Parliament.
· Article 12: Parliament is composed of two bodies: the Assembly of Deputies and the Senate.
· Article 13: The Assembly of Deputies is elected through a system of indirect census suffrage, ensuring representation from a broad base of the propertied and educated classes.
· Article 14: The Senate is composed of members elected by a higher electoral college and members by right: the Metropolitan bishops, diocesan bishops, and the heads of the princely house, creating a conservative and stabilizing counterweight.
· Article 15: The Prince convokes Parliament annually and has the right to dissolve the Assembly of Deputies, with the obligation to call for new elections within three months.

Title IV: The Executive Power

· Article 16: The Prince exercises executive power through responsible ministers, whom he appoints and dismisses.
· Article 17: Every act of the Prince must be countersigned by a minister, who thereby becomes responsible for it.
· Article 18: Ministers can be impeached by the Assembly of Deputies and judged by the Senate for acts of treason or violation of the Constitution.

Title V: The Judiciary

· Article 19: Justice is administered in the name of the Prince by courts which shall decide in his name. Judges are irremovable and independent in their function.

Title VI: Final Provisions

· Article 20: The national colors of Romania shall be Blue, Gold, and Red. The coat of arms and the national anthem shall be established by princely decree.
· Article 21: The capital of the United Principalities is the city of Bucharest.
· Article 22: Any revision of the Fundamental Law must be proposed by the Prince or either chamber and can only be adopted by a two-thirds majority of both chambers sitting separately.

Following the completion of the constitution , Leopold I starts connecting the country by railways. 
The first long railway line projected is drafted in April 1867, the line Starts in Craiova and ends in Ismail (the port city of Romania) this railway cross through:
Craiova, Bucharest , Braila , Galati and Ismail.     This project was ambitious but realistic , it aimed to  connect the major cities of Wallachia with eachother , and also connect the capital to the port city , getting access to more imported materials, goods , etc. 
Another major project of the king would be the modernization of the capital , that would  take place along 20 years.  
The goal would be to create a Berlin-style capital , not like Paris in our timeline. Engineers from Prussia  were called to help. 

Chapter 5: the military

The military underwent a strict military reform.
The hierarchy of the military was changed on merit , not on birth of status.
The military got a new uniform , based on the Prussian uniform.

The military service became mandatory for every male aged 21.

King Leopold also called upon the Prussians for a military mission to help, the mission did indeed come and it was successful at helping the Romanian army.

To help the Romanian military grow, several military universities were built in almost every major city:
Bucharest had: 
1. “universitatea militară regele Leopold I”
2. “Universitatea militară Țepeș Vodă.
Iași had:
“universitatea militară Ștefan cel mare”
Craiova had:
“Universitatea militară Basarab”

These were all built with one goal:
Attract a lot of people to the army.

Chapter 6: the long Industrial Revolution 

Romania began industrializing in 1871, after sending several Romanian military missions to the Franco-Prussian war , the Prime Minister (Ion C. Brătianu) and King decided to modernize.

The military industry was invested on but not by a lot , the main industries were:
Metallurgical industry , Mining , oil , chemical industry and textiles.

The oil production especially helped boost Romania become a small economic power, but it was a long way from becoming Belgium.


Chapter 7: the 1877-1878 war of independence 


The decades of reform under Leopold I were about to face their ultimate trial. The flames of rebellion, long simmering in the Ottoman Balkans, erupted in 1875. In Bucharest, the public sentiment fiercely supported their fellow Orthodox Christians, and the political class saw a historic opportunity. Yet, Prince Leopold and his Prime Minister, Ion Brătianu, were not impulsive men. They remembered the lessons of the past and, crucially, the reports from their military observers in the Franco-Prussian War of 1870-1871.

Those officers had returned with critical insights: the supremacy of the breech-loading rifle, the devastating effect of modern artillery, and the absolute necessity of General Staff planning and railroad logistics for a modern, mobile war. The Romanian Army, now molded in the Prussian image—from its Pickelhaube helmets to its blue-coated uniforms and its meritocratic officer corps—was ready. But diplomacy would be its first battlefield.

When the Russian Empire began its march south in 1877, it expected the Romanians to simply step aside as they had in the past. They were met with a firm, unified government in Bucharest. Leopold I, leveraging his German lineage and Romania's new-found stability, did not beg for terms; he negotiated from a position of strength. The result was the Treaty of Bucharest, signed in April 1877. It was not a request for passage, but a pact between allies. Its core tenets were clear:

1. The Russian Empire formally recognizes the full and unconditional independence of the United Principalities of Romania.
2. The Romanian Army will operate as a sovereign, independent force under its own command, acting in concert with the Russian war effort.
3. The territorial integrity of Romania is inviolable.

With the treaty ratified, the order for mobilization was given. The investments in the "Iron Paths" paid immediate dividends. Troops and materiel that once would have taken weeks to move were transported via the Craiova-Bucharest-Brăila railway to the Danube front in a matter of days. The sight of tens of thousands of Romanian soldiers, their Prussian-style uniforms a sea of disciplined blue and steel, deploying with an efficiency that stunned foreign observers, was a powerful declaration of national maturity.

The war's pivotal moment came at the Siege of Plevna. The Ottoman forces, dug into formidable redoubts, had bloodily repulsed multiple Russian assaults. The Russian command, frustrated and bleeding, was forced to swallow its pride and formally request the assistance of the Romanian Army. It was not a order, but a plea to an ally.

Under the command of General Alexandru Cernat, a product of the new military academies, the Romanian divisions moved into position. The assault on the Grivița redoubts was not a chaotic charge, but a methodical, Prussian-style operation. Modern Romanian artillery, purchased from Krupp, laid down a precise and devastating barrage. Then, the infantry advanced in disciplined lines, their Peabody-Martini rifles laying down a withering fire. The fighting was brutal and house-to-house, but the Romanians proved their mettle. The fall of Plevna was, in no small part, a Romanian victory.

At the Congress of Berlin in 1878, Romania's delegation, led by the formidable Mihail Kogălniceanu, now an elder statesman, did not plead. They presented facts. They highlighted the Treaty of Bucharest, the independent command, and the decisive military contribution. The argument was unassailable: a sovereign ally cannot be dismembered. To strip Romania of Southern Bessarabia would be an act of illegitimate aggression, and the Great Powers, particularly Britain and Austria-Hungary seeking a strong buffer to Russia, agreed.

The verdict of the Congress was a national triumph. The United Principalities were universally recognized as the independent Kingdom of Romania. Most importantly, the national territory remained intact. Southern Bessarabia was retained, securing the Danube Delta. The question of Dobruja was moot; having achieved its core national goal without sacrifice, Romania made no claim on the region, which was subsequently awarded to Bulgaria. Romania emerged from the conflict not only independent but whole, respected, and forged in the fire of war. The kingdom forged by Cuza and consolidated by Leopold I had proven itself on the world stage.

Chapter 8: the kingdom of Romania

In 1879, the Kingdom of Romania was created, no longer just a principality.

King Leopold I and Queen Antonia I were crowned in Curtea de Argeș, the first capital of Wallachia.
And the new anthem was created, “Trăiaaca regele”. 
For the first time in history , Romania didn’t just survive, but thrive. 

Romania in 1879