[3] These proximate groups (speaking mutually-intelligible but phonetically varying dialects which include Gaddang, Ga'dang, Baliwon,[4] Cauayeno, Majukayong, Katalangan,[5] Itawit, and Yogad, as well as historically documented tongues such as that once spoken by the Irray of Tuguegarao) are depicted in cultural history and official literature today as a single people.

Julian Malumbres was writing his Historia de Nueva-Vizcaya y Provincia Montanõsa[28] (published after the American takeover), which carefully details the doings of the individual priests, administrators, and military persons throughout the several hundred years of the occupation.

Important parts of the Gaddang story was lost to colonial suppression, the ravages of armed-conflict, careless or disinterested record-keeping/maintenance during inconstant administrations, and lack of documentary ability or interest among the historic population.

Unlike the Aeta hunter-gatherers or Cordilleran terrace-farmers, the Indo-Malay colonists of this period practiced swidden farming, and primitive littoral/riparian economies – collective communities that favor low population-density, frequent relocation, and limited social ties.

[56] In the 14th century the short-lived and ineffective Mongol Yuan dynasty collapsed in a series of plagues, famines, and other disasters;[57] it led to the Ming policy of Haijin ("isolation"), and a substantial increase in Wokou piracy in the Luzon Straits.

[64] Even allowing for inefficiencies in early Spanish census methodology, data supports a claim that – over a mere quarter-century – military action and disease caused major population decline (40% or more) among the natives.

In 1621, residents of Bolo led by Felipe Catabay and Gabriel Dayag commenced a Gaddang (or Irraya) Revolt[83] against the severe Church requisitions of labor and supplies, as Magalat had rebelled against Crown tribute at Tuguegarao a generation earlier.

A generation later, Gaddang returnees — at the invitation of Fray Pedro De Santo Tomas — reestablished communities at Bolo and Maquila, though the location was changed to the opposite side of the Cagayan from the original village.

Many Gaddang eventually returned to the valley, however, accepting Spain and the Church to follow the developing lowlands-farming lifestyle, taking advantage of material benefits not available to residents of the hills.

[87] With more than 680 households (3,000–4,500 people), the substantial size of these two Magat Valley Gaddang towns (100 kilometers from what is now Ilagan City) is an argument for more than a century's existence of a major native population in the area.

[88] The Gaddang are mentioned in Spanish records again in connection with the late-1700s rebellion of Dabo against the royal tobacco monopoly; it was suppressed in 1785 by forces dispatched from Ilagan by Governor Basco, equipped with firearms.

The Census also catalogues populations of the Cagayan lowlands, with theories about the origins of the inhabitants, saying: Ilokano have also migrated still further south into the secluded valley of the upper Magat, which constitutes the beautiful but isolated province of Nueva Vizcaya.

The Army built roads, bridges, hospitals, and public buildings, improved irrigation and farm production, constructed and staffed schools on the U.S. model, and invited missionary organizations to establish colleges.

During the first years of the 20th century, American administrators documented several cases throughout the islands of Filipino individuals being involved in the sale or purchase of Ifugao or Igorot women and girls to be domestic servants.

[105] In 1903 the Senior Inspector of Constabulary for Isabela wrote to his superiors in Manila: "In this province a common practice to own slaves... Young boys and girls are bought at around 100 pesos, men (over) 30 years and old women cheaper.

"[106] The regular sale of "non-Christian" Cordilleran and Negrito tribesfolk to work as farm labor in Isabela and Nueva Vizcaya was documented (a practice noted even during the Spanish administration[107]), and several Gaddang were listed as purchasers.

One Gaddang 26th Cavalry private, Jose P. Tugab, claimed he fought in Bataan, escaped to China on a Japanese ship, was with Chiang Kai-shek at Chunking and US/Anzac forces in New Guinea, then returned to help free his own Philippine home.

While Gen.Homma's main force proceeded to Ilocos Norte along the coast, troops were deployed to administer the agriculturally rich Cagayan Valley and facilitate Japanese appropriation of food supplies (butchering of more than half of farmers' carabao for meat to feed their army[117]) and farm equipment.

[143] In the essentially-rural Gaddang "homelands" (Isabela, Nueva Vizcaya, and Quirino, plus adjoining municipalities in Cagayan and Mountain provinces) the rate of increase has surpassed the national level driven by the growth of large cities.

[160] US occupation of the Philippines engendered massive re-evaluation of land-tenure based on grants to the Crown of Spain and the Church during the Spanish period; this introduced an early framework for concepts of collective indigene rights.

At present, a Nueva Vizcaya Gaddang Indigenous People's Organization has been formed, and by 2019 this group has been involved with coming to an agreement with agencies developing irrigation projects in Bayombong and Solano.

[183] During the first years of the American occupation, residents of Nueva Vizcaya towns used to schedule community events (e.g.: plays or meetings) to be held in Gaddang and the next day in Ilokano, in order to ensure everyone could participate and enjoy them.

[191][192] His recent book (Weeds, Roads, and God, 2013) explores the transition these traditional peoples are making into the modern rural Philippines, taking on more customs and habits of the lowlands Gaddang, and discarding some colorful former behaviors.

Through the end of the 20th century, some traditional highlands Gaddang practiced kannyaw – a ritual including feasting, gift-giving, music/dance, ancestral recollections and stories – similar to potlatch – which was intended to bring prestige to their family.

[181] These terms have long fallen into disuse, but comparing old parish records with landholdings in desirable locations in Bagabag, Bayombobg, and Solano indicates that some real effects of class distinctions remain active.

In a period where hostilities were a recurring phenomenon, expressed in head-taking and revenge, kinship obligations were the linkage between settlements; such kin-links include several (like solyad – or temporary marriage) which have no counterparts in modern law.

Modern Christian Gaddang funerals in homelands areas have the remains most commonly entombed in a public or private cemetery, following a Mass celebration and a procession (with a band if possible).

They may include the deadly (but never-seen) agakokang which makes the sound of a yapping dog; aled who disguise themselves a pigs, birds, or even humans, infecting those they touch with a fatal illness; the vaporous aran which enters a person's brain and causes rapidly-progressing idiocy and death; or the shining-eyed bingil ghouls.

Three hundred years of Spanish/Catholic cultural dominion – followed by a nearly effective revolution – have almost completely diluted or even eradicated any useful pre-colonial literary, artistic or musical heritage of the lowland Cagayan peoples, including the Gaddang.

Early Spanish records made little mention of customs of the Ibanagic and Igaddangic peoples, being almost entirely concerned by economic events, and Government/Church efforts at replacing the chthonic cultures with a colonial model.