Final answer:
The question mistakenly refers to 'Santiago' as a country once ruled by Spain. The capital of Chile is Santiago, and Chile was ruled by Spain until its independence.
Step-by-step explanation:
The country that was once ruled by Spain and called Santiago is Chile. In the early colonial period, Spain established a powerful overseas empire, which included territories in both the Americas and the Far East. Various regions that eventually became independent countries were named differently back then, often after saints or significant events.
Santiago, as a name linked to Spain's colonial rule, refers to the city of Santiago de Compostela in Spain itself. However, it's important to note that Chile's capital is Santiago, and the region itself was part of the Spanish Empire until its independence in the 19th century.