The Gupta Empire (319 CE - 470 CE) 👑
Gupta dynasty was initially a small kingdom which was a vassal state of the Kushans. Later during Chandragupt I's reign it became an independent Empire limited to the Ganga Valley. Samudragupta the Great became the Emperor in 319 AD as per Gupta records. He was a great military commander who conquered Bengal, Kamrupa(North east),Kalinga, Dakshin Koshal,Vengi, Pallava kingdom, parts of Vatakata dynasty, later Kushan Empire in eastern Punjab and Kashmir.
As per Sri Lankan records Ceylon accepted the Suzerainty of the Gupta Empire during Samudragupta's rule. He also maintained relations with the Western Kshatrapas, Kushans of Afghanistan and Punjab and EVEN SOUTH EAST ASIAN KINGDOMS. It is quite possible that about mentioned Kingdoms accepted his suzerainty INCLUDING INDONESIA AND MALAYSIA.
Samudragupta was succeeded by Chandragupt ii Vikramaditya (as per some texts Ramgupta). Chandragupta ii Vikramaditya subjugated Western Kshatrapas, Bactria and also defeated the Sassanid Empire. He crossed Sapta Sindhu to conquer these Lands. Vatakatas and Kadambas remained his Vassal states.
Source: Allahabad Pillar Inscriptions, Chandragupta ii Vikramaditya's Delhi pillar inscriptions, Ceylonese records Raghuvamsha and various articles relating to the topic including my self study.