It was in 1631 that the lady of Taj, Mumtaj Mahal died during birth of their 14th Child Gauhara Beghum. After 1 year of her death, construction of Taj Mahal Began. It was completed in 1648 and surrounding buildings were finished in next 5 years.
The Taj Mahal was finished in nearly 18 years from the death of the queen who was meanwhile interred in the Tomb. When it was being built, Tavernier saw it and wrote that twenty thousand workmen were continuously employed. Shah Jahan was a prolific builder and a refined aesthetic. Long before Taj Mahal was completed, the other palaces in the Agra Fort were ready.
In 1648 Shah Jahan completed the Jama Masjid in Agra which was dedicated to his daughter Jahanara, the daughter of his father who took the place of her mother and brought her father out of mourning.
The Moti Masjid or Pearl Mosque, which has features quite similar to that of the Saint Basil's Cathedral in Moscow, was completed in 1653. However the supreme masterpiece of art dedicated to eternal love was Taj Mahal.
Who was the architect of the Taj is a question that is still not answered satisfactorily. Several names are associated with this work such as Abd ul-Karim Ma'mur Khan, Makramat Khan, and Ustad Ahmad Lahauri.
Out of them Ustad Ahmad Lahauri, a Persian is thought to be the principal architect, evident by some document left by his son.
But it has been debated in the scholarly circles that the chief architect of Taj Mahal was an Italian Geronimo Veroneo. Geronimo Veroneo did visit Agra in the year 1640, but there are no evidences to prove that he was the chief architect of Taj Mahal.