Introduction:
Gana-sangha, also known as the early republic, is a term used by historians to describe a form of governance that existed in ancient India. This system was characterized by the participation of various ganas or tribes in the decision-making process. Historians refer to gana-sangha as an early republic due to several reasons, which will be discussed in detail below.

1. Democratic Elements:
The gana-sangha system exhibited democratic characteristics, which is one of the fundamental features of a republic. Decision-making was not limited to a single ruler or a small group of elites, but rather involved the participation of the entire community. The ganas, which were autonomous tribes, had the power to elect their leaders and participate in the decision-making process. This decentralized power structure is reminiscent of early republics.

2. Equality and Fraternity:
Another reason why historians refer to gana-sangha as an early republic is the emphasis on equality and fraternity within the system. In this form of governance, the ganas were considered equal and had a sense of fraternity among them. Each gana had a voice in the decision-making process, regardless of its size or power. This egalitarian approach is a characteristic often associated with republics.

3. Absence of Monarchy:
The gana-sangha system did not have a centralized monarchy or a hereditary ruler. Instead, power was shared among the ganas, and leadership positions were typically filled through elections. This absence of monarchy aligns with the concept of a republic, where power is not concentrated in the hands of a single individual or family.

4. Self-Governance:
Gana-sangha was a system of self-governance, where each gana had its own governing structure and decision-making processes. The ganas enjoyed a degree of autonomy and were responsible for managing their internal affairs. This decentralized model of governance is often associated with early republics, where local communities have a significant role in governing themselves.

Conclusion:
In conclusion, historians refer to gana-sangha as an early republic due to its democratic elements, emphasis on equality and fraternity, absence of monarchy, and the system of self-governance. The gana-sangha system in ancient India represented a form of decentralized governance where power was shared among autonomous tribes, resembling the characteristics often attributed to early republics.