Page "History of Chad" Paragraph 6

Most states began as kingdoms, in which the king was considered divine and endowed with temporal and spiritual powers.

All states were militaristic ( or they did not survive long ), but none was able to expand far into southern Chad, where forests and the tsetse fly complicated the use of cavalry.

Control over the trans-Saharan trade routes that passed through the region formed the economic basis of these kingdoms.

Although many states rose and fell, the most important and durable of the empires were Kanem-Bornu, Baguirmi, and Ouaddai, according to most written sources ( mainly court chronicles and writings of Arab traders and travelers ).