The Principalia or noble class was the ruling and usually educated upper class in the pueblos of the Spanish Philippines, comprising the gobernadorcillo (who had functions similar to a town mayor), and the cabezas de barangay (heads of the barangays) who governed the districts. The distinction or status of being part of the principalia was a hereditary right. However, it could also be acquired, as attested by the royal decree of 20 December 1863 (signed in the name of Queen Isabella II by the Minister of the Colonies, Jose de la Concha). This distinguished upper class was exempted from tribute (tax) to the Spanish crown during the colonial period.
Pre-colonial principalities
From the beginning of the colonial period in the Philippine, the Spanish government built on the traditional pre-conquest socio-political organization of the barangay and co-opted the traditional indigenous princes and their nobles, thereby ruling indirectly. The barangays in some coastal places in Panay, Manila, Cebu, Jolo, and Butuan, with cosmopolitan cultures and trade relations with other countries in Asia, were already established principalities (Kinadatuan) before the coming of the Spaniards. In other regions, even though the majority of these barangays were not large settlements, yet they had organized societies dominated by the same type of recognized aristocracy and lordships (with birthright claim to allegiance from followers), as those found in more established, richer and more developed principalities. The aristocratic group in these pre-colonial societies was called the datu class. Its members were presumably the descendants of the first settlers on the land or, in the case of later arrivals, of those who were datus at the time of migration or conquest.  The duty of the datus was to rule and govern their subjects and followers, and to assist them in their interests and necessities. What the chiefs received from their followers was: to be held by them in great veneration and respect; and they were served in their wars and voyages, and in their tilling, sowing, fishing, and the building of their houses. The natives attended to these duties very promptly, whenever summoned by their chief. They also paid their chief tribute (which they called buwis) in varying quantities, in the crops that they gathered. The descendants of such chiefs, and their relatives, even though they did not inherit the Lordship, were held in the same respect and consideration, and were all regarded as nobles and as persons exempt from the services rendered by the others, or the plebeians (timawas). The same right of nobility and chieftainship was preserved for the women, just as for the men.  Some of these principalities and lordships have remained, even until the present, in unHispanicized  and mostly Lumad and Muslim parts of the Philippines, in some regions of Mindanao.

Q: What were the pre-colonial princibalities?
A: From the beginning of the colonial period in the Philippine, the Spanish government built on the traditional pre-conquest socio-political organization of the barangay

Q: How did this affect the government?
A: In other regions, even though the majority of these barangays were not large settlements, yet they had organized societies
What are some interesting aspects about this article?
The duty of the datus was to rule and govern their subjects and followers, and to assist them in their interests and necessities. What the chiefs received
The duty of the datus was to rule and govern their subjects and followers, and to assist them in their interests and necessities. What the chiefs received