In North Sumatra, archaeological excavations on settlements dating from the historical era started at the beginning of the 1970s with researches conducted in Kota Cina, a site located on the east coast, between Medan and Belawan. This settlement, dated between the end of the eleventh century CE and the first half of the fourteenth century CE, notably yielded imagery almost certainly of south Indian origin (McKinnon 1984, 1994, 1996, 2003).

Some ten years later, a team of archaeologists at the National Research Centre for Archaeology of Indonesia conducted the first test pits in Barus on the opposite coast. The outcome of this initiative led to the launch in 1995 of a joint French-Indonesian archaeological research programme focused on the coastal site of Lobu Tua. It was completed in 2000 after five stages of excavations on this settlement dated between mid-ninth and the end of the eleventh century (Guillot (ed.) 1998; Guillot et al. 2003).

A new joint research programme was set up the following year involving the École française d'Extrême-Orient and the National Research Centre for Archaeology of Indonesia, in order to study the main ancient settlements of Tapanuli, an area covering roughly the western half of the North Sumatra province. The first phase, between 2001 and 2005, was focused on other settlements in the Barus area, especially the site of Bukit Hasang founded during the twelfth century (Perret & Surachman (eds.) forthcoming). With the knowledge accumulated during these eleven years on the west coast, the team then started a second phase in 2006, moving to the study of inland sites. Padang Lawas, an area well known for its numerous Hindu-Buddhist temple remains, was the logical choice for this phase. From that year, excavations have been conducted twice in the site of Si Pamutung.

When combined with previous discoveries, the finds collected during recent surveys and excavations bring new perspectives on the nature and intensity of the relations between Tapanuli and South Asia, especially south India and Sri Lanka, between mid-ninth century and the beginning of the fourteenth century.