The website http://www.historytoday.com/cr-boxer/spaniards-cambodia then goes paywall.The Spaniards in Cambodia
By C.R. Boxer
Published in History Today Volume 21 Issue 4 April 1971
Early Modern (16th-18thC) Cambodia, Spain Empire
Nearly four centuries ago, long before the French and the Americans, writes C.R. Boxer, the Spaniards intervened in Cambodia.
The story of spanish intervention in Cambodia during the last decade of the sixteenth century is familiar, at least in outline, to students of the history of South-east Asia. It may be worth recalling this bizarre episode for a wider public at the present time, when the unfortunate Khmer kingdom finds itself again involved with its more powerful neighbours. At the risk of over-simplification, the complicated and constantly shifting background to the actual Spanish intervention may be sketched in broad outline as follows.
Angkor, the famous group of temples and capital city of the Khmer empire of Cambodia, which had once dominated most of Indochina, had been taken and sacked by the Thais from Ayuthia in 1430-31, and subsequently abandoned for over a hundred years. The Thai monarchs thenceforward claimed suzerainty over Cambodia, which they regarded as a vassal state, and they endeavoured to instal puppet rulers whenever the frequent succession disputes in the weakened and shrinking Khmer kingdom gave them the opportunity to intervene.
Wikipedia offered
I know the Portuguese were here around that time, as traders, and I 'm sure Lucan has more about this. Anybody else hear about this?The Cambodian–Spanish War[1] (1593-1597) was an attempt by the Spanish Empire to conquer Cambodia, establish their own king, and Christianize the population.[2] Along with the Spanish, the Japanese, Filipinos, Thai, Portuguese, and Dominicans participated in the invasion of Cambodia.[3]
Cambodian–Spanish War
Date 1593-1597
Location Cambodia, Phnom Penh
Result Cambodian victory
Belligerents
Flag of Cambodia (pre-1863).svg Cambodia Spanish Empire
Commanders and leaders
Luis Pérez Dasmariñas
Gregorio Vargas Machuca
Blas Ruiz de Hernan Gonzales
Belhoso
Strength
Cambodian, Malay, and Cham forces Spanish, Portuguese, and native Filipinos
Each country possessed different motives for their invasion of Cambodia. Specifically, the Thai interference and the Spanish expedition was a result of a power struggle between rival factions in Cambodia's government.[4] In addition, both Spanish and Portuguese took part in the invasion of Cambodia because King Philip II ruled both Spain and Portugal.[5]
In February 1593, Thai ruler Naresuen attacked Cambodia in order to fight the Burmese.[6] Later on, in May 1593, 100,000 Thai (Siamese) soldiers invaded Cambodia.[7] As a result of the Thai's invasion, Lovek was conquered in July 1594.
In 1593, the Spanish expedition led by Gregorio Vargas Machuca and Blas Ruiz de Hernan Gonzales entered Cambodia through the city of Manila.[8]Although the Spanish invasion of Cambodia (supported by Luis Pérez Dasmariñas) failed, Ruiz and Veloso succeeded in establishing king Barom Reachea II in May 1597.[9]
Private individuals of Muslim Malays, Chams, Cambodians retaliated to Spain and Portugal's invasion by slaughtering the Spanish and Portuguese, including Diogo Veloso.[10][11] Only a few Filipinos and one Spaniard survived the massacre.[12] Because of the massacre, Spain's planned Christianization of Cambodia failed.[13] After the attack, Cambodia came under the dominance of the Thai in July 1599.[14]