It was in Bohol were local chieftains Datu Sikatuna of Bool and Datu Sigala of Loboc performed the Sanduguan or El Pacto de Sangre with Spanish conquistador Miguel Lopez de Legazpi back in the 16th century. The sanduguan or blood compact was a pact of friendship sealed in blood.

It is touted as the world's "first treaty of friendship between different races". The guys supposedly drank droplets of each other's blood mixed in with wine. A monument marks the spot where the blood compact was made. It is located along the road with a spectacular view of the sea.

Baclayon Church is known as the oldest stone church in the Philippines. Built in 1595 by the Jesuits, this ancient massive edifice still retains its century-old architectural design. Both in the external and internal portions of the church, it contains various interesting relics and artifacts dating back to the early 16th century.

Another equally beautiful church in the island are the Alburquerque Church and the Tagbilaran Church, which are also built with precious and sturdy limestones.

Sources:

http://psychosanctum.blogspot.com/2008/03/breathtaking-bohol-sanduguan.html

http://www.globalpinoy.com/travel/province/bohol.php