The Kingdom of the Algarve (Portuguese: Reino do Algarve, from the Arabic Gharb al-Andalus غرب الأندلس), later the Kingdom of the Algarves (Portuguese: Reino dos Algarves), was a nominal kingdom within the Kingdom of Portugal.
It was the second dominion of the Portuguese Crown and supposedly a kingdom apart from Portugal, though in fact the Algarvian kingdom had no institutions, special privileges, or autonomy. In actuality, it was just an honorific title for the Algarve based on its history and was very similar to the rest of the Portuguese provinces.
The title King of Silves was first used by Sancho I of Portugal after the first conquest of Silves in 1189. As this conquest did not take all of the Algarve, Sancho never used the title King of Portugal and the Algarve, but instead it was adopted by his grandson Afonso III of Portugal as a part of the titles and honours of the Portuguese Crown.
During the Reconquista, Portuguese and Castilian conquests went south, to take lands from the Muslims that they claimed as theirs. Portugal conquered and secured much of its southern borders during the reigns of King Sancho II of Portugal and King Afonso III of Portugal.
In 1189, King Sancho I of Portugal conquered Silves, one of the most prosperous cities in Al-Andalus, aligned at the time with the Almohad Caliphate. Portuguese control over Silves would be short, with the Almohads conquering the city again in 1191 in a massive counter-attack led by Abu Yusuf Yaqub al-Mansur the Almohad Caliph in person.