In the post-Vedic period, the entire northern territory mostly situated north of the Vindhyas and extending from the North-West frontier to Bihar was divided into sixteen states called Sodasha Mahajanapadas. These Mahajanapadas were either monarchical or republican in character. Examples of monarchical mahajanapadas are; Magadha: Between Anga and Vatsa there lay the kingdom of Magadha, corresponding to modern Patna and Gaya districts, bounded on the north and west by the rivers Ganga and Son, on the south by the Vindhya outcrop and on the east by the river Champa.
Vatsa: The Vatsa country had a monarchical form of government. Its capital was Kausambi (identified with the village of Kosam, 38 miles from Allahabad. Kausambi, a very prosperous city was the most important entre pot of goods and passengers from the south and the west.

Magadha and Vatsa as Monarchical Mahajanapadas

Magadha and Vatsa were two prominent Mahajanapadas during the ancient period in India. Both of them were characterized by having a monarchical form of government, where a king ruled over the territory.

1. Magadha
- Magadha was one of the most powerful and prosperous Mahajanapadas in ancient India.
- It was located in the eastern part of present-day Bihar and parts of Uttar Pradesh.
- The capital city of Magadha was Rajagriha, which later shifted to Pataliputra (modern-day Patna).
- Magadha was ruled by several dynasties, including the Haryanka dynasty and the Shishunaga dynasty.
- The most famous ruler of Magadha was King Bimbisara, who expanded the kingdom through military conquests.
- Bimbisara was succeeded by his son Ajatashatru, who further expanded the boundaries of Magadha.
- Magadha's military strength, fertile land, and strategic location played a significant role in its rise to prominence.
- Magadha later became the center of the powerful Mauryan Empire under the rule of Chandragupta Maurya and his successors, who unified most of India.

2. Vatsa
- Vatsa was another important Mahajanapada located in present-day Uttar Pradesh.
- Its capital city was Kausambi, situated on the banks of the Yamuna River.
- Vatsa was ruled by the Vatsa dynasty, which belonged to the Bharata clan.
- Udayana was one of the famous kings of Vatsa, known for his patronage of arts and literature.
- Vatsa was also known for its economic prosperity and trade connections with other Mahajanapadas.
- However, it did not achieve the same level of dominance as Magadha.

Conclusion
Both Magadha and Vatsa were significant Mahajanapadas during ancient India. While Magadha emerged as a powerful kingdom and later became the center of the Mauryan Empire, Vatsa had its own influence and prosperity. Both Mahajanapadas had a monarchical form of government, with a king as the central authority.