Various Persian tribes subsequently made swipes at South Asia but the next big epoch-changing event came when the Muslim Arabs, whose ships used to sail the Indian Ocean in the general direction of Singapore, got lost and accidentally sailed up the Indus river. Sensing the extreme welcome of the locals, they soon conquered the nation of Sind and set up shop as the first Muslim kingdom in South Asia under the leadership of Mohammad Bin Qasim. Mohammad Bin Qasim is seen by the Pakistanis as a sort of Christopher Columbus figure. You will find many things in Pakistan named after him - ports, bridges, restaurants, even people.

The locals soon integrated these invaders into their local customs. Despite retaining their Muslim faith, the invaders generally got along with their neighbours and things went quiet for a few centuries.

By 1200, Central Asia was stirring. The Turkic tribes inhabiting Central Asia were nominally Muslim, but in reality, their real inspiration were the Vikings - loot and pillage being their normal modus operandi. Soon enough, they noticed the signs at the Khyber Pass and decided to invade South Asia. The South Asians, of course, laid out their usual customary welcome mats and a regular cycle was quickly established - wave after wave of invasion from Central Asia.

The thing usually ran like this. A Turkic speaking tribe would invade from the Khyber, make the run down to Delhi and ransack the place. Along the way, raiding the local Hindu and Buddhist temples, usually full of gold, was a particularly popular activity. Half the invaders would eventually return to Central Asia with the loot while the remainder would stay back and rule over the locals. The invaders who remained would soon "go native" - in other words become lovers of nature, art, music, dance and fine food. They would marry the local women and lose their previous war-fighting instincts. Life would once again become peaceable in Delhi and normal order would be restored.

A century later a new Turkic tribe would come down the Khyber, find the locals to be extremely welcoming and repeat the exercise. Thus Delhi would see the rise and fall of many Central Asian dynasties. The invading folks were keen on ostentatious mausoleums so we can still see their tombs dotted around parts of Delhi. While the locals, given their hospitable ways, did not do much to stop the invading hordes, they did keep score of the brutality meted out to them. This excellent record-keeping would lead to much instability in the centuries to come.

Back in Central Asia, a new type of Muslims - the Sufis - had started to make their mark in society. To some degree these Sufis resembled Christian or Buddhist monks in their worldview. Peace-loving, kind, ascetic, they were also keen proselytisers of Islam. The Turkic rulers did not mind them much because they helped to stabilise society and given their placid nature, never posed a threat to the ruling elite.

Soon the Sufis were making a mark in South Asia too. Large parts of the local population were converting to Islam. It was no longer a case of the outsiders from Central Asia ruling over the local Hindus and Buddhists. A large polity of local Muslims now started forming an establishment clique below the ruling Turkic overlords. Some of the local Hindus and Buddhists, sensing economic opportunity, converted to Islam to climb up the social ladder - the locals operated a "caste system" which made the social order very formal, so there was much to be gained from jumping a layer or two by converting to the religion of the ruling elite. The Muslim minority became sizeable and things started to get a bit more volatile.

The first signs of real friction between the Muslims and the Hindus was now visible, the Buddhists having shrunk in number to be too small a community to influence events. The population remained overwhelmingly Hindu, who still made up at least three-quarters of the total, but economic prosperity was very much skewed towards the ruling Muslim elite. The consequences of this injustice would play out over and over again in the centuries to come.

And so South Asia existed in this way until the beginning of the 16th century when the Mongols arrived at the Khyber Pass c.1500.