5 October 1910 revolution in the context of "First Portuguese Republic"

This is a list of Portuguese monarchs who ruled from the establishment of the Kingdom of Portugal, in 1139, to the deposition of the Portuguese monarchy and creation of the Portuguese Republic with the 5 October 1910 revolution.

Through the nearly 800 years in which Portugal was a monarchy, the kings held various other titles and pretensions. Two kings of Portugal, Ferdinand I and Afonso V, claimed the crown of Castile and waged wars in order to enforce their respective claims. Ferdinand I managed to be recognized as King of Galiza in 1369, although his dominance of the region was short-lived. When the House of Habsburg came into power, the kings of Spain, Naples, and Sicily also became kings of Portugal. The House of Braganza brought numerous titles to the Portuguese Crown – some honorary, such as the attribution of the title of Rex Fidelissimus (His Most Faithful Majesty), and royal titles, such as King of Brazil and then de jure Emperor of Brazil.

Saxe-Coburg and Gotha (German: Sachsen-Coburg und Gotha), or Saxe-Coburg-Gotha (German: Sachsen-Coburg-Gotha [ˈzaksn̩ ˈkoːbʊʁk ˈɡoːta]), was an Ernestine duchy in Thuringia ruled by a branch of the House of Wettin, consisting of territories in the present-day states of Thuringia and Bavaria in Germany. It lasted from 1826 to 1918. In November 1918, Charles Edward, Duke of Saxe-Coburg and Gotha, was forced to abdicate. In 1920, the northern part of the duchy (since 1918 the Free State of Gotha; culturally and linguistically Thuringian) was merged with six other Thuringian free states to form the Free State of Thuringia: Saxe-Weimar-Eisenach (until 1918 a grand duchy), Saxe-Altenburg and Saxe-Meiningen (until 1918 duchies), Schwarzburg-Rudolstadt and Schwarzburg-Sondershausen (until 1918 principalities), as well as the People's State of Reuss (until 1918 the principalities of Reuss-Gera and Reuss-Greiz). The southern part of the duchy (since 1918 the Free State of Coburg; culturally and linguistically Franconian), as southernmost of the Thuringian states, was the only one which, after a referendum, became part of the Free State of Bavaria.

The name Saxe-Coburg-Gotha also refers to the family of the ruling House of Saxe-Coburg and Gotha, which played many varied roles in the dynastic and political history of Europe in the 19th and 20th centuries. In the early part of the 20th century, before the First World War, it was the family of the sovereigns of the United Kingdom, Belgium, Portugal, Bulgaria, and Saxe-Coburg-Gotha. In 1910, the Portuguese king was deposed, and the same thing occurred in Saxe-Coburg-Gotha in 1918 and in Bulgaria in 1946 (although effective control had already ceased two years prior due to a coup). As of 2025, a branch of the family still reigns in Belgium, and while the British line still technically exists up to the present day, it now uses the name Windsor due to a proclamation issued by King George V in 1917. The former Tsar of Bulgaria, Simeon II (reigned 1943–46), kept his surname while serving as the Prime Minister of Bulgaria from 2001 to 2005.

The Constitution of Portugal, officially the Constitution of the Portuguese Republic (Constituição da República Portuguesa), is the supreme law of Portugal. It superseded the Estado Novo's 1933 Constituion on April 25, 1976 after the Carnation Revolution.

The Consitution was preceded by a number of constitutions including the first one created in 1822 (following the Liberal Revolution of 1820), 1826 (drawn up by King Dom Pedro IV), 1838 (after the Liberal Wars), 1911 (following the 5 October 1910 revolution), and 1933 (after the 28 May 1926 coup d'état).