Ok, before I post those pics from that Dutch museum (it's the Tropenmuseum, in Amsterdam, and then later I'll also post pics from other European museums), let me just quickly summarize the cosmology and religion then in archipelagic Southeast Asia.
In essence, the key beliefs or religions were two -- [1] animism, including the belief in a tripartite cosmos that's ruled by certain key deities, and [2] ancestral worship.
As discussed above, spirits and deities were believed to inhabit and rule the Upperworld and the Underworld. And inanimate natural & man-made objects were also believed to be 'alive' -- rock formations, rivers, boats, swords, etc. All these were part of the animistic religion.
Now aside from the above spirits, departed ancestors were also believed to inhabit the tripartite cosmos. And so these ancestors were also venerated and called upon in times of need. This would be then the other half of the core beliefs -- ancestral worship.
In the illustration below thus, I've added an Igorot
bulul as symbol for the ancestral worship component of the olden beliefs.