Spanish annexation of the Dominican Republic

The Annexation of the Dominican Republic to Spain (Spanish: Anexión de la República Dominicana a España) or Reintegration of Santo Domingo (Reintegración de Santo Domingo) was a four-year period between 1861 and 1865 during which the former Spanish possession of Santo Domingo in the eastern part of the island of Hispaniola, then the independent Dominican Republic, was occupied and annexed by the Spanish Empire, following the request of Dominican dictator Pedro Santana. The period coincided with the American Civil War, during which the United States was unable to enforce the Monroe Doctrine.

Source: Wikipedia — Spanish annexation of the Dominican Republic (CC BY-SA 4.0)