According to expert opinion, Balarama, as the chief of the original quadruple forms, is also the original Sankarsana. Balarama, the first expansion of Krsna, expands Himself in five forms:
(1) Maha-sankarsana,
(2) Karanodakasayi,
(3) Garbhodakasayi,
(4) Ksirodakasayi, and
(5) Sesa.
These five plenary portions are responsible for both the spiritual and material cosmic manifestations. In these five forms Lord Balarama assists Lord Krsna in His activities. The first four of these forms are responsible fo