From the third century AD when the Hun invasion ended the Roman Empire, the Indian merchants relied more and more on the

After the third-century disruptions to Indo-Roman links (including the Huna invasions and the decline of Roman trade), Indian merchants turned increasingly to the maritime networks of Southeast Asia. Archaeological and literary evidence shows southern India’s ports were integral to long-distance sea routes that connected the Indian subcontinent with Southeast Asian markets, and material links with Southeast Asia are attested at many sites [1]. Scholarship also notes that the Huna-related decline in western (Roman) trade coincided with growth and diversion of Indian maritime commerce towards eastern routes and Southeast Asian contacts, reinforcing Indian engagement with island and mainland Southeast Asian polities for spices, timber and luxury goods.

Sources

1. [1] History , class XI (Tamilnadu state board 2024 ed.) > Chapter 5: Evolution of Society in South India > 5.6 Society and Economy > p. 69