Ambrosio Rianzares Bautista y Altamira (December 7, 1830 – December 4, 1903), also known as Don Bosyong, was a Filipino lawyer and author of the Declaration of Philippine Independence. A distant relative to the Rizal family and the Bonifacio family, Bautista often gave advice to José Rizal, a Filipino nationalist, while studying in Manila.^[1]

Bautista was born in Biñan, La Laguna (now Laguna) to Gregorio Enriquez Bautista and Silvestra Altamira. He attended preparatory school in Biñan and studied law at University of Santo Tomas, obtaining a degree in 1865. He practiced law in Manila and offered free legal services to poor clients. Whilst practicing law, Bautista, on his way to Malolos, Bulacan, was captured by a group of bandits, who subsequently learned that he saved many of their friends as a defender of the poor in court cases against rich Filipinos and Spaniards. The bandits apologized to Bautista and set him free.

Bautista solicited funds to finance a campaign for reforms in the Philippines, later becoming a member of the La Liga Filipina, Cuerpo de Compromisarios and La Propaganda. In 1896, the Spaniards arrested and imprisoned him at Fort Santiago, as he was suspected of being involved in the Philippine Revolution; Bautista elected to defend himself and was later released from prison.

In 1898, Bautista became the first adviser to President Emilio Aguinaldo and subsequently wrote the Declaration of Philippine Independence.^[2]

Contrary to common belief, it was Bautista, and not Aguinaldo, who waved the Philippine flag before the crowd on June 12, 1898, during the Philippine Proclamation of Independence in Cavite.^[3][2]

On July 14, 1899, Bautista was elected to the position of president in Tarlac's Revolutionary Congress and was later appointed judge of the Court of First Instance of the province of Pangasinan.^[4]

• Portrayed by Richard Manabat in the 2012 film, El Presidente.

• Patricio Mariano

• Bautista Rianzares Ambrosio. 1830 - 1903 (accessed on September 10, 2007)
• Quirino, Carlos. Who's Who in Philippine History. New York: Home Books. 1995.
• National Historical Institute. Historical Markers: Regions I-IV and CAR. Manila: National Historical Institute. 1993
• "Southern Luzon and Bicol: Ambrosio Rianzares Bautista." Unsung Heroes of the Philippines Revolution - MSC Communications Technologies, Inc.. (accessed September 12, 2007).