An American anthropologist/archaeologist, Wilhelm Solheim II, recovered a significant number of potteries from Kalanay Cave, Aroroy, Masbate associated with the Early Metal Age. Through a C-14 date obtained from an adjacent site, Kalanay Cave was dated to be 2710±100 BP (Before Present) (Solheim, 1959). Solheim observed that artifacts from Kalanay resembled materials from Sa-Huynh in central Vietnam. He suggested early maritime trade across the South China Sea between Vietnam and the Philippines about 2600 years ago. Although recent archaeological studies indicate that Kalanay pottery actually bears more similarity with the later period site of Hoa Diem, also in Central Vietnam, dated to the 3rd to 4th century BCE, Solheim’s discovery in Kalanay remains significant today.
After observing similar pottery forms and decorations between Kalanay and Sa-Huynh from Central Vietnam, Solheim proposed the idea of a broader region of contact in Southeast Asia that he referred to as the Sa Huynh-Kalanay Interaction Sphere. Solheim explained that the similarities in pottery styles and traditions across the region were a result of extensive maritime exchanges between the Nusantao or Austronesian-speaking peoples of Southeast Asia in Central Vietnam and the Philippines. Solheim later expanded the Sa-Huynh interaction sphere to include Taiwan, Southern Thailand, and Northern Borneo (Solheim 1964).
The Kalanay cave site is known worldwide as a burial cave as its early inhabitants, the Kalanay people practiced burial jar inhumation. The archaeological discovery in Kalanay suggests an extensive cultural interaction between coastal communities in the Philippines, East and Southeast Asia about 2300 years ago. It also paves the way for a deeper understanding of the way of life of these prehistoric peoples.