Mahmud Khalji I, the ruler of Malwa, is said to have received a letter of investiture from the Caliph of Egypt for his military exploits.

Explanation:
1. Historical Context:
- Malwa was a region in central India that witnessed the rise and fall of various dynasties.
- The Khalji dynasty ruled over Malwa during the 15th century.
- The Khalji dynasty was of Turkic origin and had established a powerful kingdom in central India.

2. Mahmud Khalji I:
- Mahmud Khalji I was the founder of the Khalji dynasty in Malwa.
- He ruled from 1436 to 1469 AD and is known for his military exploits.
- Mahmud Khalji I expanded his kingdom by conquering neighboring regions and consolidating his power.

3. Letter of Investiture:
- The Caliph of Egypt was the religious and political leader of the Islamic world during that period.
- It was customary for Muslim rulers to seek recognition and legitimacy from the Caliph.
- Mahmud Khalji I's military successes and expansion of his kingdom must have caught the attention of the Caliphate.

4. Significance of the Letter:
- The letter of investiture from the Caliph of Egypt was a prestigious recognition for Mahmud Khalji I.
- It affirmed his position as a legitimate ruler and acknowledged his military achievements.
- The letter also symbolized the close ties between the Khalji dynasty and the Islamic world.

5. Implications:
- The receipt of the letter of investiture would have boosted Mahmud Khalji I's prestige and authority.
- It would have enhanced his standing among his subjects and neighboring rulers.
- The recognition from the Caliphate could have also facilitated diplomatic relations and trade with other Islamic states.

In conclusion, Mahmud Khalji I, the ruler of Malwa, received a letter of investiture from the Caliph of Egypt for his military exploits. This recognition elevated his status as a legitimate ruler and strengthened his ties with the Islamic world.