This Spanish stamp, issued in 1899, features a youthful portrait of King Alfonso XIII, often referred to as the "Child King" due to his accession to the throne as an infant. The design shows him in military attire, framed by ornate detailing, with the denomination 15 Céntimos printed in bold numerals. Printed in violet, this issue belongs to the "Medallón" series, a classic representation of Spain’s late 19th-century philatelic history. A popular collectible, it reflects both Spain’s royal heritage and transitional postal period. A fine addition for collectors focusing on Spanish monarchy or 19th-century European issues.