Complex sentence: Rodrigo de Vivero y Velasco was the Spanish Governor-General of the Philippines and gave an eye-witness account in 1608-09, describing the huge stones that made up the walls and the large number of people at the castle.
Split into simpler sentences: Rodrigo de Vivero y Velasco was the Spanish Governor-General of the Philippines and gave an eye-witness account in 1608-09. He described the huge stones that made up the walls and the large number of people at the castle.