It was the practice in previous centuries that the mortal remains of, usually, prominent persons were buried inside the church. This was so since these families were patrons or benefactors who, in one way or another, contributed to its construction, donated precious jewels, saints, vestments and other church decorations or even paid for the upkeep of a chapel. In some instances, they sponsored the priests who were assigned there. In some other instances, they paid for the chapel or a slot for their final resting place.
San Agustin is no exception. When one enters the church, at the lobby or narthex and looking down, one would notice that a part of the floor have inscriptions, just like lapidas or
Perhaps, the most prominent person interred in the church is that of the founder of the city of Manila: Adelantado Miguel Lopez de Legazpi. Unfortunately, during the British invasion, they ransacked the tombs to look for hidden treasures that when the Augustinian friars reclaimed the church after the British left, it was mixed with the other remains.
Now in the Legazpi chapel, a memorial is posted:
IN MEMORIAM Aqui yacen los restos mortales del Adelantado Legaspi y su nieto Salcedo, Lavezares, Beato P. Pedro de Zuniga y otros heroes de la conquista. Los que aventados por los Ingleses en 1762. Confundidos y revueltos fueron colocados por los P. P. Agustinos en esta capilla
This translates to:
IN MEMORY Here lies the mortal remains of Adelantado Legazpi and his grandsons Salcedo, Lavezares, Blessed Pedro de Zuniga, and other heroes of the Conquest; the British defiled them in 1762; the Augustinian Fathers relocated them here without any identification.
The cryptocollateral chapels were usually paid for by patrons thus, more tombstones can be seen with many of these with intricately carved lapidas (above right). One of the chapels, the Chapel of the Assumption, was obtained by the Zobel de Ayalas, Sorianos and Roxases families around 1893 and now hold their remains (above left).