Spain has had a number of constitutions through the years. The first was in the early 19th Century, and the current one dates to the late 20th Century.

As the 19th Century began, France was at war with many other European powers. Spain at that time was an ally of sorts. However, the French Emperor Napoleon Bonaparte eventually decided that he wanted a familiar face on the Spanish throne and so, in 1808, demanded the abdication of Spain's then-current monarch, Charles IV, and, eventually as well, his son, Ferdinand VII. The new King of Spain was Joseph Bonaparte, Napoleon's brother.

Bayonne Statute
To solidify this new rule, Emperor Bonaparte directed one of his top generals, Joachim Murat, to hammer out an agreement with powerful Spanish nobles. The result was the Bayonne Statute, also called the Bayonne Constitution (Bayonne being the place in France at which occurred the meetings, including the one in which the two kings abdicated). Along the lines of France's most recent multi-layered government, the Bayonne government was to have a three-part government, consisting of a legislature, a large number of government ministers, and an independent judiciary. Catholicism was declared the state religion; the constitution guaranteed other individual liberties. As well, the Philippines and areas in the New World still controlled by Spain won the right to representation in the new government.

Focusing on the vestiges of the once broad Spanish Empire, the Constitution of 1812 granted indigenous people living in Spanish-controlled New World lands (such as the Viceroyalty of New Spain and the Viceroyalty of Peru) full Spanish citizenship. The glaring exception to this was enslaved people, who continued to have few rights.

This constitution was also known as the Constitution of Cádiz because it had the solid support of the Cortes of Cádiz, a new form of the parliament-equivalent cortes, which had not been in operation for awhile.

Technically, from 1812, Joseph Bonaparte was a constitutional monarch. When he fled the country in the wake of a series of victories by a joint British-Portuguese force, Ferdinand VII filled the vacuum and claimed the throne again, in 1814. He refused to acknowledge the constitution or its parliament and, with the backing of the army and some powerful nobles, ruled as an absolute monarch.

A mutiny of troops in 1820 sparked a wider revolt that succeeded in taking King Ferdinand prisoner. Thus distracted, the king could only receive reports from abroad as one by one of his overseas possessions gained their freedom. Ferdinand was technically still king, but his people had taken away his mystique and, technically, his right to dictate terms.

Into Spain's internal fray in 1823 came a French army, sent by that country's king, Louis XVIII, to try to restore Ferdinand's absolutism. He and they were successful, the rebel force releasing the king after the French victory in the Battle of Trocadero. Ferdinand remained the sole governmental authority until his death, in 1830.

His designated successor was, controversially, his 3-year-old daughter, Isabella. While her mother, Queen Maria Christina, served as regent, a sizable part of the population rose up in revolt, sparking the first of three Carlist Wars, named after Carlos, the Count of Medina, who was Ferdinand's younger brother and thought his a better case for succession than that of young Isabella.

Constitution of 1876
Amadeo ruled for two years and then abdicated, in the wake of the declaration of the First Spanish Republic. Three years after that, Spain had another new monarch, Alfonso XII. To cement his status as a consitutional monarch, a group of nobles again got together and again approved a new governmental blueprint, the Constitution of 1876. The king and parliament shared legislative powers. The king had the power to appoint ministers, without needing parliamentary approval. In fact, the king had the power to suspend or even dissolve the Cortes. As well, this constitution brought a return of the establishment of Catholicism as the state religion and the public worship of other faiths punishable. Initially, the Constitution of 1876 provided for election of parliament by census suffrage, whereby those who had more power had effectively more votes; in the 1890s, however, parliament re-established universal male suffrage.

In 1923, Spanish General Miguel Primo de Rivera launched a coup and declared himself a dictator. The king, Alfonso XIII, approved of the move, and Rivera was in charge until 1930. Public opinion of the dictatorship and the king's support for it waned. Alfonso XIII became highly unpopular and, after a disastrous showing in the 1931 elections, agreed to leave the country, in favor of the founding of the Second Spanish Republic.