In the Mālavikāgnimitram, act 5, verse 14, Kālidāsa tells us that Vasumitra guarded the sacrificial horse let loose by his grandfather Pushyamitra Shunga and he defeated a cavalry squadron of the Yona (Indo-Greeks) on the banks of the Indus River.
[2][3][4] At the news of the victory of her son Vasumitra, Dharini promises to reward Mālavikā, gives her to the King and gladly consents to their union.
Vasumitra's victory played a vital role in the union of his father Agnimitra and Mālavikā.
[2] Banabhatta's Harshacharita mentioned him as Sumitra and informed us that he was killed by Mitradeva (or Muladeva, according to some manuscripts) while enjoying a drama.
The secession of Kosala extinguished the Shunga hold over territories west of Magadha but also must have encouraged other rulers to rebel and declare independence.