In ancient times the area was mostly part of Vanga, a non-Aryan territory covering the eastern part of the Gangetic delta. According to some writers it also covered territories east of the old course of the Brahmaputra 
The impact of Aryan-Brahmana culture was felt in Bengal much after the same spread across northern India. The various non-Aryan people then living in Bengal were powerful and thus the spread of Aryan-Brahman culture was strongly resisted and the assimilation took a long time.
In a map published in his book Indica, the Greek traveller Megasthenes, who visited in 302 BC, presents the entire Mymensingh area and much beyond in Kamarupa. In 4th century AD, during the reign of Samudragupta, the region (whole of Kamrupa) was part of the Gupta Empire. During his visit to the area in 639-45 AD, the Chinese monk, Xuanzang (Hiuen Tsang) found both Buddhism and Jainism flourishing in Bengal. According to certain records, some parts of the Mymensingh area, which was part of Pundravardhana in 7th century AD, was restored to Kamrupa between the 8th and 10th centuries. Subsequently, some small kingdoms, subservient to the Pala Empire were there in area. While Sishu Pal, Harishchandra Pal and Jasho Pal, ruled in the southern portions, Bhag Dutta (who ruled in Kamrupa) established himself in the Madhupur tract.
In the 12th century Ballal Sena divided his kingdom into five parts – Rarh, Bagri, Barendra, Mithila and Vanga. While Barendra was the area bounded by the Mahananda, and the Padma and the Karotoya, Vanga was the area between the Karatoya and the Brahmaputra. It is evident that the area east of the Brahamaputra was part of Kamrupa and the area west of the Brahmaputra was part of the Sena Empire. However, there is a difference of opinion amongst historians about where exactly Vanga was and some feel that even the western portion of the Mymensingh area was part of Kamrupa. In the 13th century Kamrup broke up and small kingdoms surfaced in the Mymensingh area. In the 14th century the bhati region was captured by a sannyasi (hermit) named Jitari. The bhati region normally refers to the extreme western part of old Mymensingh.