Short answers, pulled from the story.
Sri Gupta is identified as an independent monarch in the Magadha region around the late 3rd century CE. Recent numismatic research confirms his sovereign authority through over one hundred silver coins discovered in Bihar.
Kalidasa wrote plays such as Abhijnanashakuntalam while Aryabhata developed a place value system and approximated pi to four decimal places. Varahamihira composed the Pancha Siddhanta and Vatsyayana authored the Kama Sutra which remains a standard work on human sexual behaviour.
Heavy cavalry formed the core of the army supported by war elephants light infantry horse archers chariotry and ships. The five arms included infantry cavalry chariotry elephantry and ships according to historical records from the Allahabad Pillar inscription.
Alchon Huns under Toramana broke through defences in the northwest overrunning much empire by 500 CE. King Yashodharman from Malwa drove the Huns out of India in 528 after Bhanugupta defeated Toramana in 510.
King Vishnugupta is recognized as the tail end ruler reigning from 540 to 550 CE with his last known inscription made in 542 or 543 CE. Modern genetic studies indicate Indian caste groups ceased intermarrying starting during this period while archaeological evidence points to a devastating flood around the middle of the 6th century.