Hindus, were being slowly converted to Islam. The process was not rapid. Some changed their religion because Islam appealed to them,

Jawahar Lal Nehru in his Book titled as minorities.  Racially India is a patchwork and a curious mixture, but no racial questions have arisen or can arise in India.  Religion transcends these racial differences, which fade into one another and are often hard to distinguish.  Religious barriers are obviously not 'Glimpses of World History' (Published by Oxford University Press) has given detailed this in Chapter 66.  Relevant passage finds place at page 214 of the Book, the same is being quoted below:-
".....Meanwhile, the people of the country, the Hindus, were being slowly converted to Islam.  The process was not rapid.  Some changed their religion because Islam appealed to them,  some did so because of fear, some because it is natural to want to be on the winning side.  But the principal reason for the change was economic.  People who were not Muslims had to pay a special tax, a poll tax-jezia, as it was called.  This was a great burden on the poor.  Many would change their religion just to escape it.  Among the higher classes desire to gain Court favour and high office was a powerful motive....."

How the assessment of amount of jezia tax was payable by Hindu population is clear from the Book titled as 'The Administration of the Moghul Empire' written by a Historian Ishtiaq Husain Qureshi.  The relevant passage is being quoted below:-
"...The assesses were divided into three categories in accordance with their wealth.  Those in possession of ten thousand dirhems or more were considered to be wealthy; those who had less than ten thousand but more than two hundred dirhems were classified as belonging  to the middle class, those who had less than two hundred dirhems but enough, in addition to the cost of maintaining themselves and their dependents, to pay the tax were considered to be poor.   The first category was required to pay forty-eight dirhems per annum; the second twenty-four; and the third twelve.  These seem to have been the rates for the urban areas; in the countryside the government levied a flat charge of four per cent of the state demand upon agricultural produce.  If the agents of government failed to collect the jiziyah from any one for an entire year, he could not be charged the sum later.  A dirhem was roughly 550 English grains of silver..."
The history further makes it clear that population of any community played a vital role for affecting India's polity as well as Geography.  Afghanistan was part of Greater India as Gandhar.  It was also part of Greater India up to 1739 A.D. and Buddhism was a dominant religion in Afghanistan.  Conversion of Buddhists into Islam in Afghanistan started process of separation which completed in 1739 AD when Nadirshah separated Afghanistan from India and merged in his empire.  After death of Nadirshah Afghanistan became an independent Muslim State.  Due to Islamic Rule for more than one thousand years in Sindh, Punjab, North Western Frontier Provinces and Bengal Hindu majority  were converted into Muslim.  In the year 1945, the percentage of Muslim population was 54 per cent and Hindus were 45 per cent and others were 1 per cent in Bengal only.  Due to certain privileges to Muslims in India Greater India was partitioned in 1947 on the basis of two nations theory that the Muslims and Hindus constitute two nations.  Present problem in Kashmir valley is also problem of Majority Muslim population whereas there is no such problem in Jammu and Laddakh where Hindus and Buddhists are in majority.  History also makes it clear that due to special privileges to Muslims for more than one thousand years during Muslim Rule, though they were in microscopic minority and special separate rights to Muslims were given by Britishers also after 1906 upto Inidia was actually partitioned on the basis of Muslim population in undivided India.  It is clear that population coupled with special rights awarded to  Muslims, detailed above, played a greater role in changing history and geography of this country.  
As has already been discussed above which is a historical fact that majority of Muslims were converted Hindus and has origin of Hindus ancestors who adopted Muslim religion for various reasons during the period of more than one thousand years of Islamic Rule in the country and the majority of conversion took place due to economic reason of poor who could not pay Jezia Tax compulsorily made payable by Hindu population.  Historic  Book 'Glimpses of World History' written by Pt. Jawahar Lal Nehru makes it clear that conversion from Hindu community to Muslim religion during muslim Rule  took place mostly due to poverty and due to non-payment of Jezia Tax. It is only after the end of the Muslim rule, Hindus and Muslims jointly fought against Britishers in 1857 AD-the first war of independence against foreigners to re-establish India's own rule.   This common-ness and nationhood lasted not for more than 50 years, when Muslim League was established in 1906 which started claiming separate rights on the ground of religion which was conceded by Congress as well as British Parliament which ultimately resulted in division of the country on the basis of religion and changed Geography of India.
The above careful study of the history makes it clear that minority rights were  given for protecting their right and not to claim any privilege or special rights in comparison to Hindus, but  to remove  sense of insecurity and lack of confidence in minority, who opposed partition of India,  but this minority right was misinterpreted by certain quarters and inspite of the fact that at present the population of Muslim Religious group is more than 18.5 per cent, they are  still claiming themselves as religious minority community, though neither there is any insecurity nor there is any lack of confidence in Muslims whereas Muslim Religious group has now become single largest religious dominant group on the basis of population & strength affecting all walks of life including democratic process.   It is further clear that in some States of India Muslim population is about 25 per cent and at least more than 13.8% on all India basis.  In this backdrop, now Muslims have become a dominant group in all respects and have ceased to be a Religious minority community. As the matter before the Court is relating to Uttar Pradesh, hence the Court is expressing opinion only with regard to Muslim Religious community in Uttar Pradesh.  This Court has taken note of historical background, judgments of Apex Court and debates of Constituent Assembly and is of the view that any further recognition of Muslims as a religious minority community will necessarily give rise to multinationalism in India and as such the State of Uttar Pradesh as well as Central Government may consider and pass appropriate orders to delete entry of Muslims as a religious minority community in India.
The above discussions made it clear that ancestors of present Hindu society fought and saved their religion, civilization and culture even by paying Jezia Tax for continuing as Hindu in Islamic Rule in different parts of India and present Indian generation should be grateful for saving their religion, culture and civilisation even under such odd situation.
It is further clear from the History that it was Akbar who did not impose any Jezia tax, but the same was re-imposed lateron by Aurangjeb.
During the period of Muslim Rule for about one thousand year, no member of Muslim community claimed any minority rights.  The Britishers thereafter tookover the administration of India.  First war of Independence in 1857  was fought by both Hindus and Muslims jointly.    After 1857, first war of independence, certain social, political and religious awakening took place in the Indian society.  A number of social reformers and religious leaders emerged who worked in the Indian Society some of them  were Swami Dayanand  Sarswati who established Arya Samaj, Sri Raja Ram Mohan Rai, Swami Vivekanand and various other awakening and political changes also took place in the Indian society towards their rights in this era.  
From the Book 'Discovery of India' by Pt. Jawahar Lal Nehru  following facts are borne out that how concept of minority was developed in pre independence era:-
Indian National Congress was also established in 1885 and thereafter in 1906, Indian Muslim League was established by some Muslim leaders.  Under the banner of Indian National Congress, Hindus and Muslims both participated in the national movement of Independence under the leadership of  national leaders belonging to both the communities and ultimately under the leadership of Mahatma Gandhi movement for independence gained momentum.  But, Muslim League started claiming separate electorate/franchise  for Muslims even prior to 1935.