The Laguna Copperplate Inscription (Filipino: Inskripsyón sa binatbát na tansô ng Laguna) is an official acquittance certificate inscribed onto a copper plate in the Shaka year 822 (Gregorian A.D. 900). It is the earliest known calendar-dated document found within the Philippine Islands.^[1]

The plate was found in 1989 by a laborer near the mouth of the Lumbang River in Wawa, Lumban, Laguna, in the Philippines. The inscription was mainly written in Old Malay using the Early Kawi script, with several technical Sanskrit words and Old Javanese or Old Tagalog honorifics.^[2] After it was found, the text was first translated in 1991 by Antoon Postma,^[3] a Dutch anthropologist and Hanunó'o script researcher.^[1]

The inscription documents the existence and names of several surrounding states as of A.D. 900, such as the Tagalog city-state of Tondo.^[1] Some historians associate the toponym Medang in this inscription regarding the Medang palace in Java at that time, although the name is a common term of Malayo-Polynesian origin.^[1]

The inscription is made out of copper and measures about 20 by 30 centimeters (7.9 in × 11.8 in), with the words directly embossed onto the plate. It differs in manufacture from Javanese scrolls of the period, which had the words inscribed onto a heated, softened metal scroll.^[4]

It records the date as the year 822 of the Shaka era, the month of Vaishakha, and the fourth day of the waning moon on the weekday of Somavara, which corresponds to Monday, April 21, 900, on the Julian calendar.^[5] The text is Old Malay, with numerous loanwords from Sanskrit and a few non-Malay vocabulary elements whose origin may be Old Javanese.^[1] The Sanskrit words are used for technical terms, while the Javanese words are used for forms of address. The Old Malay it uses differs from examples found in Java and Sumatra.^[6] The document states that it releases its bearers, the children of Namwaran, from debt in gold amounting to 1 kati and 8 suwarnas (865 grams; 27.8 troy ounces).^[4][7]

Postma, who first translated the Laguna Copperplate Inscription, suggested that the place names and personal names in the inscription needed to be carefully studied by scholars because "they furnish vital clues regarding the political and topographic background" of the world around the time of the inscription. He identified as toponyms the words Pailah, Tundun, Puliran, and Binuangan, and posited that Dewata and Medang could be either personal names or toponyms. Postma identified three of these toponyms, Binuangan, Pailah, and Puliran, as Malayo-Polynesian in origin, and three other toponyms, Tundun, Dewata, and Mdang, as being of Sanskrit origin.^[1]

After carefully considering possible interpretations of the text, including the possibility that Pailah and Puliran were located in the Laguna Lake region, Postma concluded that he was confident that Binuangan, Pailah, and Puliran "find their equivalents within the limited area of what is now known as Bulacan Province in the Philippines, [and that] the text of this same inscription can be considered to refer indeed to these places, already existing already under identical names in the tenth century".^[1] The text itself, however, being written in 900, was created in the ninth century.

The Laguna Copperplate Inscription, among other recent finds such as the Golden Tara of Butuan and 14th-century pottery and gold jewelry in Cebu, is highly important in revising ancient Philippine history, which was until then considered by some Western historians to be culturally isolated from the rest of Asia, as no evident pre-Hispanic written records were found at the time. Philippine historian William Henry Scott debunked these theories in 1968 with his Prehispanic Source Materials for the Study of Philippine History, which was subsequently published in 1984.^[14] The locations mentioned are all near rivers, suggesting Old Malay may have come to the area along trade networks.^[6]

The inscription is a document demonstrative of pre-Hispanic literacy and culture and is considered a national treasure. It is currently deposited at the National Museum of Anthropology in Manila.^[15]

It is the earliest document that shows the use of mathematics in precolonial Philippine societies. A standard system of weights and measures is demonstrated by the use of precise measurement for gold, and familiarity with rudimentary astronomy is shown by fixing the precise day within the month in relation to the phases of the moon.^[16]

Prior to the European colonial era, Southeast Asia was under the Indosphere of greater India, where numerous Indianized principalities and empires flourished for several centuries in what are now Myanmar, Thailand, Indonesia, Malaysia, Singapore, Brunei, the Philippines, Laos, Cambodia, and central and southern Vietnam. The influence of Indian culture in these areas was given the term indianization.^[17] French archaeologist George Coedes defined it as the expansion of an organized culture that was framed by the Indian origins of royalty, Hinduism and Buddhism, and the Sanskrit dialect.^[18] This can be seen in the Indianization of Southeast Asia, the spread of Hinduism, and the transmission of Buddhism. The Indian diaspora, both ancient (PIO) and current (NRI), played an ongoing key role as professionals, traders, priests, and warriors.^[19][20][21] Indian honorifics also influenced Malay, Thai, Filipino, and Indonesian honorifics.^[22]

The pre-colonial native Filipino script called Baybayin (ᜊᜌ᜔ᜊᜌᜒᜈ᜔), known in Visayan as badlit (ᜊᜇ᜔ᜎᜒᜆ᜔), as kur-itan/kurditan in Ilocano, and as kulitan in Kapampangan, was itself derived from the Brahmic scripts of India. Its use was recorded in the 16th century by Miguel López de Legazpi.^[23]

The inscription shows heavy Sanskrit and Old Javanese linguistic influences.^[4] Among the observations made by Antonio Pigafetta in the 16th-century Boxer Codex was that Old Malay had currency among classical-period Filipinos as a lingua franca. The Golden Tara statue, an ancient artifact discovered in Butuan, Agusan del Norte, dates from the same period and strongly suggests the presence of Hindu–Buddhist beliefs prior to the introduction (and subsequent subscription) to Roman Catholicism and Islam among Filipinos.^{[citation needed]}

These inscriptions are all from the province of Central Java, Indonesia (excepting for the Kalasan inscription, which is in the adjacent Special Region of Yogyakarta).

• Canggal inscription (732)
• Kalasan inscription (778)
• Kelurak inscription (782)
• Karangtengah inscription (824)
• Tri Tepusan inscription (842)
• Shivagrha inscription (856)
• Mantyasih inscription (907)

The Laguna Copperplate Inscription was found in 1987 near the mouth of the Lumbang River near Laguna de Bay^[24] by a man named Ernesto Legisma, who was dredging sand to turn it into concrete. Suspecting that the artifact might have some value, the man sold it to an antique dealer, who, having found no buyers, eventually sold it to the National Museum of the Philippines, where it was assigned to Alfredo E. Evangelista, head of its anthropology department.^[4][25] The National Museum refers to the artifact as the Laguna Copper Plate.^[26]

A year later, Antoon Postma noted that the inscription was similar to the ancient Indonesian script of Kawi. Postma translated the script and found the document dated itself to the Saka year 822, an old Hindu calendar date that corresponds to the year 900.^[3] It is from about the same time as the mention of the Philippines in the official Chinese Song dynasty History of Song for the year 972.^[27]