Mahmud was the son of Subuktigin and his policy of conquest brought him in India just like his father who had extended his kingdom beyond the Indus after a reign of 20 years. He was a brilliant general and a mighty conqueror. He led as many as 17 expeditions into India during the years 1000-1206. Out of these the one against the temple of Somnath in 1025 AD was the most important as it gave Mahmud a vast treasure.
1000 AD: Hindushahi Kingdom was attack- border areas and some strategic forts occupied.
1001-02 AD: Peshawar and Waihind attacked Jaipal taken captive but released on the payment of ransom.
1004-05 AD: Attack at the fort of Bhatiya (Bhatia) situated on trade route from the Khyber Pass to Multan. Its ruler Bhaji or Biji Rai gave a heroic fight but was defeated.
1006 AD: Multan attacked. Its ruler Fateh Daud sought help from Hindushahi Anandapal-both were defeated.
1006-07 AD: Biji Rai of Behra defeated. Behra handed over to Sukhpal who converted to Islam. Later, he repudiated Islam and was dismissed and taken prisoner.
1008-09 AD: Second battle of Waihind; Nagarkot plundered rulers of Ujjain, Gwalior, Kalinjar, Kannauj, Delhi and Ajmer were also defeated.
1009-10 AD: Narayanpur, near Alwar (Rajasthan) was attacked. Is ruler was defeated and has to part with his entire treasury.
1010-11 AD: Multan annexed. King Daud who had failed to act as faithful ally and reverted to old heretic practices was taken prisoner and deposed. Mahmud appointed a Turkish military officer as governor of Multan.
1011-12 AD: Thaneswar attacked.
1013-14 AD: Nandanah occupied.
1015-16 AD: Kashmir campaign proves abortive.
1018-19 AD: Kannauj plundered.
1020-21 AD: Kalinjar invaded.
1021-22 AD: Lahore invaded
1025-26 AD: Plunder at Somnath
1027 AD: Punitive campaign against Jats of Indus region.
1. Little or no attention was paid to internal strengthening and organisation of the empire.
2. Excess use was made of military power in external security.
3. Mahmud Ghazni had incompetent successors.
4. Lack of definite and universal law relating to succession to throne resulted in constant fight among the successors of Mahmud.
5. Alauddin Hussain, a Gaud king, attacked Ghazni in 1155 AD. Khusro Malik, the last ruler, was killed by Mohammad Ghur in 1192 AD.
6. There was a lack of control over the army.
7. There was no new source of income except plunder or war booty.
Mahmud was posed as a great, but ‘Shikan or destroyer of the image’ for the glory of Islam. He patronised three persons- Firdausi (Poet), Alberuni (Scholar), Utbi (Historian). He did not make any systematic effort to capture Indian territories, except for that held by the Shaiya dynasty. However, Mahmud may be seen as the founder of Turkish rule in India to the extent that his conquests opened India to conquest from the north-west.