The ancient Oc Eo of the Mekong Valley in Southern Vietnam was a culture with an extensive canal system, buildings with brick foundations, and trade relations with other ancient civilisations including Rome, India and China. In documents written around the 3rd century by agents of the Chinese Emperor Wu, Oc Eo is described as having walled palaces and a sophisticated system of taxation. Pottery is among the various Oc Eo objects discovered since 1944, when the French archaeologist Louis Malleret (1901–70) began excavations in the region. Round-bottomed bowls such as this were described by Malleret as creuset or crucible. The stamped grooves marking the base suggest the pot was strong enough to withstand heating and may have been used for cooking or for smelting materials such as glass. The pots were made of clay from local sources, mixed with various tempers including sand, shells and plant residue.