<P> On March 24, 1897, Velez and his men marched towards Yauco, planning to attack the barracks of the Spanish Civil Guard, to gain control of their arms and ammunition . At arrival, they were ambushed by Spanish forces . When a firefight broke out, the rebels quickly retreated . On March 26, a group headed by Jose Nicolas Quiñones Torres and Ramon Torres fought Spanish colonial forces (mostly island men) in a barrio called Quebradas of Yauco, but were overcome . The government arrested more than 150 rebels, charged them with various crimes against the state, and sent them to prison in the City of Ponce . These attacks became known as the Intentona de Yauco (Attempted Coup of Yauco). It was the first time that the flag of Puerto Rico was flown on the island . </P> <P> Velez fled to St. Thomas where he lived in exile . Mattei Lluberas went into exile in New York City, joining a group known as the "Puerto Rican Commission". </P> <P> After four hundred years of colonial rule by the Spanish Empire, Puerto Rico finally received its sovereignty in 1897 through a Carta de Autonomía (Charter of Autonomy). It was signed by Spanish Prime Minister Práxedes Mateo Sagasta and ratified by the Spanish Cortes . </P> <P> A few months later, the United States claimed ownership of the island as part of the Treaty of Paris of 1898, which concluded the Spanish--American War, which they had won that year . The Puerto Rican Nationalist Party formed in reaction, and has always held that, by international law, the Spanish had no authority under the Treaty of Paris to cede the island, which was no longer theirs . The Nationalist movement attracted supporters following the repressions by the island government in the Ponce and the Río Piedras massacre . The profits generated by this one - sided arrangement were enormous, as US corporations developed large plantations . </P>

When did puerto rico gain their independence from spain