The Treaty of Peace between the United States of America and the Kingdom of Spain, commonly known as the Treaty of Paris of 1898, was signed by Spain and the United States on December 10, 1898, that ended the Spanish–American War. Under it, Spain relinquished all claim of sovereignty over and title to territories described there as the island of Porto Rico and other islands now under Spanish sovereignty in the West Indies, and the island of Guam in the Marianas or Ladrones, the archipelago known as the Philippine Islands, and comprehending the islands lying within the following line:, to the United States. The cession of the Philippines involved a compensation of $20 million from the United States to Spain.

William Rufus Day was an American diplomat and jurist who served as an associate justice of the Supreme Court of the United States from 1903 to 1922. Prior to his service on the Supreme Court, Day served as United States Secretary of State during the administration of President William McKinley. He also served as a United States circuit judge of the United States Court of Appeals for the Sixth Circuit and the United States Circuit Courts for the Sixth Circuit.