Ancient Tamil Sangam age site Arikamedu was under Velir clans. A Brahmi inscription associated with Black & Red ware (BRW) culture mentions a Velir ruler named Yadu Balabhuti in Sanskrit. This indicates Tamil kings also had Sanskritic names along with Tamil during Sangam age.

The Velir clans traced origins to Yadavas who migrated from Dvaraka along with Rishi Agastya and settled down in south. Sangam age text Purananuru 201 mentions Velirs from Thuvarai (Dwarka?) associated with 'northern sage', possibly Agastya.

The Ay rulers who ruled southern Kerala also traced origins to the Velir clan as stated in Purananuru 135 where an Ay king is said to be descendant of Velirs.

The Ay rulers continued to associate with Yadus even after mixing with Cheras who migrated from Mahodayapuram ( now Kodungallur) long after Sangam age. Samgramadhira Ravi Varma Kulashekhara, the ruler of hybrid Chera-Ay kingdom held the title 'Yadu-shishu' in 13th century

After reign of Ravi Varma, the old Tamil patrilineal succession system was changed to matrilineal system of Nairs (marumakkathayam) with adoption of princesses from north Malabar's Kolathiri line.