The Spanish-American War, fought between April and August 1898, resulted in the United States emerging as a world power. After decisive U.S. victories in Cuba and the Philippines, a peace treaty was signed between the two countries in Paris on December 10, 1898.

However, before the formal peace treaty was signed, a protocol agreement had already been established by John Hay, the American Secretary of State, and Jules Cambon, the French ambassador to the United States. The protocol was signed on August 12, 1898, and laid out the terms for the cessation of hostilities between the United States and Spain.

Under the agreement, Spain would withdraw its troops from Cuba and cede control of Guam, Puerto Rico, and the Philippines to the United States. In return, the United States agreed to pay Spain $20 million for the Philippines.

The agreement also addressed the issue of Cuba`s future. It recognized Cuba`s independence from Spain and provided for the establishment of a temporary U.S. military government to oversee the transition to a new Cuban government. The United States also agreed to withdraw its troops from Cuba once a stable government was established.

The protocol agreement paved the way for the eventual signing of the Treaty of Paris. This treaty, which was signed on December 10, 1898, formalized the end of the Spanish-American War and established the terms of peace between the two nations.

In summary, the agreement signed by John Hay after the Spanish-American War was the protocol agreement of August 12, 1898. This agreement established the terms for the cessation of hostilities between the United States and Spain, including Spain`s withdrawal from Cuba and the cession of control of Guam, Puerto Rico, and the Philippines to the United States. It also recognized Cuba`s independence and provided for the establishment of a temporary U.S. military government until a stable Cuban government was established.