Amadeo I of Spain was a king who ruled from 1870 to 1873. Born in 1845, he was a member of the House of Savoy and was chosen as king after the abdication of Isabella II of Spain. His reign was marked by political instability and opposition from various factions, including republicans and Carlists. Despite his efforts to unify the country, Amadeo faced significant challenges and ultimately decided to abdicate the throne in 1873. After his departure, Spain transitioned into the First Spanish Republic, which further highlighted the difficulties of establishing a stable monarchy during that period.