Ghaznavid Dynasty established in 963 by Alptigin was the first Turkish dynasty in Iran who ruled Iran, Afghanistan, Pakistan and parts of northern and north western India. The capital of this dynasty was Ghazni in present day Afghanistan. It was during this era when Islam was introduced to India through several wars and attacks.
In the last years of the Samanid dynasty, Alptigin, one of the commanders from a Turkic tribe gradually achieved power and started increasing the territories under his command and of course still they were under the rule of the Samanids but were starting to act independently and finally were overthrown by them. As they had originated in Ghazni, they named the dynasty as Ghaznavid. Although the Ghaznavid were Turkic people, they were very much under the influence of the Persian Samanids and hardly can we consider them as Turks. They even supported Persian literature and poets to an acceptable extends.
The most important and famous king of the Ghaznavid was Mahmud who attacked India 17 times and captured vast areas in north and northwest of India and Islamized the Hindu part of India. But after the death of Mahmud in 1030, his successors lost most parts of the territory to another Turkic group named the Seljuqs and the dynasty ended in 1187.