Samudragupta was succeeded by his son Chandragupta II surnamed Vikramaditya.But according to some scholars the immediate successors of Samudragupta was his son Ramagupta,the elder brother of Chandragupta II. A drama Devichandraguptam by Visakhadutta mentions that Ramagupta agreed to surrender his queen Dhruvadevi to the infatuation of a Saka chief who had invaded his kingdom. The honour of the queen was saved by Chandragupta; younger brother of Ramagupta who killed the Saka chief usurped the throne and married the widow. However the historicity of Ramagupta is matter of great doubt as neither the contemporary inscriptions nor the coins mention any king of that name.Chandragupta inherited the military genius of his father and extended the Gupta Empire by conquests of his own. His principal opponent was the Saka ruler of Gujarat and Kathiawar Peninsula belonging to the family of western Satraps whose continued independence prevented the political unity of India. His efforts were crowned with success. Rudrasimha III the last of the long line of Saka satraps was killed. The annexation of Kathiawar and Gujarat not only expanded the Gupta Empire from the Bay of Bengal to the Arabian Sea but also brought it in direct contact with the western world.
The acquisition of Broach, Sopara, Cambay and other ports dotted on the western coast of India and the income from the custom duties collected at the numerous ports gave economic prosperity to the Gupta Empire. The most important entrepot at the time was Ujjain where most of the trade routes converged. The effect of this extension of the western frontier was immense on the trade and commerce as well as the culture of northern India. The European and African trade received immense help with the Gupta conquest of the Kathiawar ports. The western traders poured Roman gold into the country in return for Indian products and the effect of this great wealth on the country in noticeable in the number of coins of Chandragupta II. Chandragupta had other military conquests to his credit. An inscription engraved on the iron pillar near Qutub Minar at Delhi states that a king named Chandra defeated a confederacy of hostile chiefs in Vanga and having crossed the seven mouths of the river Sandhu conquered the Vahlikas. Chandragupta II extended the Gupta empire in all directions-west, east and north-west.