Answer by taking a quote from the following article:

Mumtaz Mahal (Urdu: mumtz mHal ), ([mum'ta:z me'hel]; meaning "the Exalted One of the palace"; Arjumand Banu; 27 April 1593 - 17 June 1631) was Empress consort of the Mughal Empire from 19 January 1628 to 17 June 1631 as the chief consort of the Mughal emperor Shah Jahan. The UNESCO World Heritage Site Taj Mahal in Agra, often cited as one of the Wonders of the World, was commissioned to act as her final resting place. Mumtaz Mahal was born Arjumand Banu Begum in Agra to a family of Persian nobility.

Upon his accession to the throne in 1628, Shah Jahan designated Mumtaz as his chief empress with the title of 'Malika-i-Jahan' ("Queen of the World") and 'Malika-uz-Zamani' ("Queen of the Age"). Mumtaz's tenure as empress was brief (spanning a period of only three years due to her untimely death), nonetheless Shah Jahan bestowed her with luxuries that no other empress was given before her. For example, no other empress' residence was as decorated as Khas Mahal (part of Agra Fort), where Mumtaz lived with Shah Jahan. It was decorated with pure gold and precious stones and had rose water fountains of its own. Each wife of the Mughal emperor was given regular monthly allowance for her gastos (housekeeping or travelling expenses). The highest allowance on record is 10 lakh rupees per year given to Mumtaz Mahal under Shah Jahan.  Shah Jahan consulted Mumtaz in both private matters and the affairs of the state and she served as his close confidante and trusted adviser. At her intercession, he forgave enemies or commuted death sentences. His trust in her was so great that he gave her the highest honour of the land -- his imperial seal, the Mehr Uzaz, which validated imperial decrees. Mumtaz was portrayed as having no aspirations to political power, in contrast to her aunt, Empress Nur Jahan, the chief consort of Emperor Jahangir, who had wielded considerable influence in the previous reign.  A great influence on him, often intervening on behalf of the poor and destitute, she also enjoyed watching elephant and combat fights performed for the court. Mumtaz also patronized a number of poets, scholars and other talented persons. A noted Sanskrit poet, Vansidhara Mishra, was the Empress' favourite. On the recommendation of her principal lady-in-waiting, Sati-un-Nissa, Mumtaz Mahal provided pensions and donations to the daughters of poor scholars, theologians, and pious men. It was quite common for women of noble birth to commission architecture in the Mughal Empire, so Mumtaz devoted some time to a riverside garden in Agra, which is now known as Zahara Bagh. It is the only architectural foundation which can be connected to her patronage.

who led
Shah Jahan