Why it's the capital
On 24 June 1571 the Spanish conquistador Miguel López de Legazpi arrived and declared Manila a territory of New Spain. It became the capital of the Spanish East Indies.
Capital of PhilippinesManila sits on the eastern shore of Manila Bay, on the island of Luzon. The Pasig River flows through the middle of the city, dividing it into northern and southern parts.
On 24 June 1571 the Spanish conquistador Miguel López de Legazpi arrived and declared Manila a territory of New Spain. It became the capital of the Spanish East Indies.
Find Luzon, the big island in the north of the Philippines, and tap the large bay on its west coast. Manila is on the eastern shore of that bay.
Quezon City, Manila's neighbour to the northeast, was the capital from 1948 to 1976. In 1976 the title went back to Manila.
Sources: Wikipedia: Manila, Wikipedia: Intramuros, Wikipedia: Quezon City