Shahab-ud-din Muhammad Khurram Shah Jahan I (also spelled Shah Jehan,Shahjehan, Urdu: شاه ‌جہاں, Persian: شاه جهان) (January 5, 1592 – January 22, 1666) was the emperor of the Mughal Empire in India from 1628 until 1658. The name Shah Jahan comes from Persian meaning "king of the world." He was the fifth Mughal ruler after Babur, Humayun, Akbar, and Jahangir. While young, he was a favourite of his legendary grandfather Akbar the great. He is also called Shahjahan The Magnificent.

Even while very young, he was pointed out to be the successor to the Mughal throne after the death of Emperor Jahangir. He succeeded to the throne upon his father's death in 1627. He is considered to be one of the greatest Mughals and his reign has been called the Golden Age of Mughals. Like Akbar, he was eager to expand his empire. In 1658 he fell ill, and was confined by his son Emperor Aurangzeb in the citadel of Agra until his death in 1666. On the eve of his death in 1666, the Mughal Empire spanned almost 750,000,000 acres (3.0E+6 km²) and he was the most famous and powerful man on earth of the age who had in his empire the biggest and the most prosperous capital (Shahjahanabad) and some of the most delicate architectural masterpieces of the world. The period of his reign was the golden age of Mughal architecture. Shah Jahan erected many splendid monuments, the most famous of which is the legendary Taj Mahal at Agra built as a tomb for his wife Empress Mumtaz Mahal (birth name Arjumand Banu Begum). The Pearl Mosque and many other buildings inside the Red Fort (Qila Mubarak) at Agra , the complete design of the Old Delhi (Shahjahanabad), the palaces, the Red Fort and the great mosque at Delhi, mosques in Lahore, buildings in the Lahore fort (present day Pakistan) and a beautiful mosque at Thatta (present day Pakistan) also commemorate him. The most famous, celebrated and the luxurious throne of the world, the Takht-E-Taus or the Takht-E-Shahanshah-E-Hindustan (Peacock Throne), said to be worth millions of dollars by modern estimates, also dates from his reign. He was also the founder of Shahjahanabad, now known as 'Old Delhi'. The important buildings of Shah Jahan were the Diwan-i-Am and Diwan-i-Khasin the fort of Delhi, the Jama Masjid, the Moti Masjid and the Taj. It is pointed out that the Palace of Delhi is the most magnificent in the East.

Baadshah Shah Jahan was born as Prince Shihab-ud-din Muhammad Khurram, in 1592 in Lahore, India (current day Pakistan) as the third and favorite son of the emperor Jahangir. The name Khurram - Persian for 'joyful' - was given by his grandfather Akbar. His early years saw him receive a cultured, broad education and he distinguished himself in the martial arts and as a military commander while leading his father's armies in numerous campaigns - Mewar (1615 CE, 1024 AH), the Deccan (1617 and 1621 CE, 1026 and 1030 AH), Kangra (1618 CE, 1027AH). He was responsible for most of the territorial gains during his father's reign. He also demonstrated a precocious talent for building, impressing his father at the age of 16 when he built his quarters within his great grandfather Emperor Babur's Kabul fort and redesigned buildings within Agra fort. He also carries the universally famous titles like "The builder of marvels ".

In 1607 CE (1025 AH), at the age of fifteen, Khurram was to marry Arjumand Banu Begum, the grand daughter of a Persian noble, who was 14 years old at the time. After their wedding celebrations, Khurram "finding her in appearance and character elect among all the women of the time," gave her the title Mumtaz Mahal (Jewel of the Palace). Mumtaz Mahal had 14 children. Despite her frequent pregnancies, she travelled with Shah Jahan's entourage throughout his earlier military campaigns and the subsequent rebellion against his father. Mumtaz Mahal was utterly devoted — she was his constant companion and trusted confidante and their relationship was intense. She is portrayed by Shah Jahan's chroniclers as the perfect wife with no aspirations to political power. This is in direct opposition to how Nur Jahan had been perceived. She died an accidental death while giving birth to her 14th child. Shahanshah Shah Jahan never remarried.

The intervening years had seen Khurrum take two other wives known as Akbarabadi Mahal (d.1677 CE, 1088 AH), and Kandahari Mahal (b. c1594 CE, c1002 AH), (m.1609 CE, 1018 AH). According to the official court chronicler Qazwini, the relationship with his other wives "had nothing more than the status of marriage. The intimacy, deep affection, attention and favor which His Majesty had for the Cradle of Excellence [Mumtaz Mahal] exceeded by a thousand times what he felt for any other." Several European chroniclers suggested that Shah Jahan had an incestuous relationship with his daughter Jahanara Begum. The French traveller Francois Bernier wrote, "Begum Sahib, the elder daughter of Shah Jahan was very beautiful... but Lal pointed out that Aurangzeb may have been involved in "magnifying a rumour into a full-fledged scandal", and wrote: "Aurangzeb had disobeyed Shahjahan, he had incarcerated him for years, but if he really helped give a twist to Shahjahan's paternal love for Jahan Ara by turning it into a scandal, it was the unkindest cut of all his unfilial acts." But no authentic proof exists that the great mughal had any such relationship.

Inheritance of power and wealth in the Mughal empire was not determined through primogeniture, but by princely sons competing to achieve military successes and consolidating their power at court. This often led to rebellions and wars of succession. As a result, a complex political climate surrounded the Mughal court in Shahzada Khurram's formative years. In 1611 his father married Nur Jahan, the widowed daughter of an Afghan Noble. She rapidly became an important member of Emperor Jahangir's court and, together with her brother Asaf Khan, wielded considerable influence. Arjumand was Asaf Khan's daughter and her marriage to Prince Khurrum consolidated Nur Jahan and Asaf Khan's positions at court.

Khurram's great military successes of 1617 CE (1026 AH) against the Lodi in the Deccan effectively secured the southern border of the empire and his grateful father rewarded him with the prestigious title 'Shah Jahan Bahadur' (Brave King of the World) which implicitly sealed his inheritance. Court intrigues, however, including Nur Jahan's decision to have her daughter from her first marriage wed Shah Jahan's youngest brother and her support for his claim to the throne led Khurram, supported by Mahabat Khan, into open revolt against his father in 1622. The rebellion was quelled by Jahangir's forces in 1626 and Khurram was forced to submit unconditionally. Upon the death of Jahangir in 1627, Prince Khurram succeeded to the Mughal throne as Shah Jahan, King of the World, the latter title alluding to his pride in his Timurid roots and his ambitious dreams of becoming a renowned ruler in history. Shahanshah Shah Jahan's first act as ruler was to execute his chief rivals and imprison his step mother Nur Jahan. This allowed Shan Jahan to rule without contention.

Although his father's rule was generally peaceful, the empire was experiencing challenges by the end of his reign. Shahanshah Shah Jahan reversed this trend by putting down an Islamic rebellion in Ahmednagar, repulsing the Portuguese in Bengal, capturing the Rajput kingdoms of Baglana and Bundelkhand to the west and the northwest beyond the Khyber Pass. Under his rule, the empire developed a huge military machine and the nobles and their contingents multiplied almost fourfold, as did the demands for more revenue from the peasantry. But due to his measures in the financial and commercial fields, it was a period of general stability — the administration was centralised and court affairs systematised. Historiography and the arts increasingly became instruments of propaganda, where beautiful artworks or poetry expressed specific state ideologies which held that central power and hierarchical order would create balance and harmony. The empire continued to expand moderately during his reign but the first signs of an imperial decline were seen in the later years when he was being imprisoned. Above all it is obligatory to mention here that India became the richest centre of the arts, crafts and architecture and some of the best of the architects, artisians, craftsmen, painters and writers of the world resided in the empire.

Under Shahanshah Shah Jahan the Mughal Empire attained its highest union of strength and magnificence. The high scale and beautiful constructions carried out during his rule caused India to be admired in arts, crafts and architecture. The land revenue of the Mughal Empire under Shah Jahan was 460 million sterling pounds, higher than any other Mughal ruler. The magnificence of Shah Jahan’s court was the wonder of all the European travelers and ambassadors from other parts of the world. His famous Peacock Throne, with its trail blazing in the shifting natural colors of rubies, sapphires, and emeralds, was valued by the jeweler Tavernier at 6½ millions sterling.

His political efforts encouraged the emergence of large centres of commerce and crafts — such as Lahore, Delhi, Agra, and Ahmedabad — linked by roads and waterways to distant places and ports. He moved the capital from Agra to Delhi.

Under Shah Jahan's rule, Mughal artistic and architectural achievements reached their zenith. Shah Jahan was a prolific builder with a highly refined aesthetic. Among his surviving buildings are the Red Fort and Jama Masjid in Delhi, the Shalimar Gardens of Lahore, sections of the Lahore Fort (such as Sheesh Mahal, and Naulakha pavilion), and his father's mausoleum. Legend has it that Shah Jahan wanted to build a black Taj Mahal for himself. There is no reputable scholarship to support this hypothesis, nor any other horrific legends that Shah Jahan maimed, blinded, or killed those responsible for designing and building his tomb.

When Shah Jahan became ill in 1658 CE (1067 AH), Dara (Mumtaz Mahal's eldest son) had assumed the role of Regent in his father’s stead which brought animosity towards him by his brothers. Upon receiving this information, his younger brothers, Shuja, Viceroy of Bengal, and Murad, Viceroy of Gujarat, declared their independence, and marched upon Agra in order to claim their riches. Aurangzeb, the third son, the ablest and most virile of the brothers joined them and being placed in chief command, attacked Dara's army close to Agra and completely defeated him. Although Shah Jahan fully recovered from his illness, Aurangzeb declared him incompetent to rule and put him under house arrest in Agra Fort. Jahanara Begum Sahib, Jahan's first daughter, voluntarily shared his 8-year confinement and nursed him in his dotage. In January of 1666 CE (1076 AH), Shah Jahan fell ill with strangury and dysentery. Confined to bed, he became progressively weaker until, on 22 January, he commanded the ladies of the imperial court, particularly his consort of later years Akbarabadi Mahal, to the care of Jahanara. After reciting the Kalima and verses from the Qu'ran, he died. Jahanara planned a state funeral which was to include a procession with Shah Jahan's body carried by eminent nobles followed by the notable citizens of Agra and officials scattering coins for the poor and needy. Aurangzeb refused to accommodate such ostentation and the body was washed in accordance with Islamic rites, taken by river in a sandal wood coffin to the Taj Mahal and was interred there next to the body of his beloved wife Mumtaz Mahal.

Shah Jahan exemplified one of the highest points in the Mughal Empire but also foreshadowed its downfall through the succession of emperors in the Mughal line. With his accession and downfall at the hands of his sons, Shah Jahan can clearly be seen as a leader who changed the landscape of India dramatically in the course of his reign; taking into consideration the legacy that brought him down as well as his great accomplishments, Shah Jahan's life exemplified the internal workings of an empire that was built through conquest, violence, and tolerance while alluding to the unstable hierarchy and the right to power in the Mughal Empire. He came to power through violence and betrayal and was ultimately brought down by the same means, exacerbating the legacy of the Mughals.

Shah Jahan has left behind a grand legacy of structures constructed during his reign. He was a patron of architecture. His most famous building was the Taj Mahal, now a wonder of the world, which he built out of love for Mumtaz Mahal. Its structure was designed with great care and architects from all over the world were called for this purpose. The building took twenty years to complete and was constructed entirely from white marble. Upon his death, his son Aurangazeb had him interred in it next to Mumtaz Mahal. Among his other constructions are the Delhi Fort also called the Red Fort or Lal Qila (Urdu) in Delhi, large sections of the Agra Fort, the Jama Masjid (Grand Mosque), Delhi, the Wazir Khan Mosque, Lahore, Pakistan, the Moti Masjid (Pearl Mosque), Lahore, the Shalimar Gardens in Lahore, sections of the Lahore Fort, Lahore, the Jahangir mausoleum — his father's tomb, the construction of which was overseen by his stepmother Nur Jahan and the Shahjahan Mosque, Thatta, Pakistan. He also had the Peacock Throne, Takht e Taus, made to celebrate his rule. A famous Seamless celestial globe was produced in 1659 - 1660 AD (1070 AH), by the Sindhi Astronomer Muhammad Salih Tahtawi of Thatta with Arabic and Persian inscriptions.

There is a crater named after Shah Jahan on the asteroid 433 Eros. Craters on Eros are named after famous fictional and real-life lovers.