Admiral Pareja had arrived at Valparaiso on…
September 1865 CE
Admiral Pareja had arrived at Valparaiso on his flagship, the Villa de Madrid, on September 17, 1865, and demanded that the Spanish flag be given a twenty-one-gun salute.
He had purposefully chosen the day before the anniversary of Chilean independence (September 18) to present his demand.
Under the circumstances, the Chileans refuse and war is declared a week later, on September 24.