Phetracha was the foster brother of King Narai, whose patronage helped him rise to become head of the Elephant Department and a leading general in the kingdom. He led the coup that toppled the Greek adventurer Constantine Phaulkon (Phaulkon, Constantine) from ministerial office and expelled a French expeditionary force from Ayutthaya in 1688. In that year he seized the throne himself and determined to drastically reduce foreign power and influence. To this end he persecuted Christians and harassed Western traders, while encouraging more easily controlled Asian traders.