Edward John Dent, a famous English watchmaker best known for his extremely accurate clocks and marine chronometers was born in London in 1790. He began working as an apprentice to his grandfather, John Wright Dent when he was 14 years old. 

Dent was so awestruck with the clock making business that his grandfather allowed him to shift as a candle maker to Edward Gaudin, to Watchmaker, on February 13, 1807.

In 1814, Dent was just 24 years old when he supplied the Admiralty with a Standard Astronomical Clock and at least one pocket chronometer for the Colonial Office African Expedition. He submitted two chronometers, Nos. 54 and 55, to Greenwich for testing in 1826.

Dent was hired by the Royal Observatory at Greenwich in 1828 to check and repair chronometers. He was described as "among the best workmen of the present day" by John Pond, the Astronomer Royal at the time, in a letter to the Board of Ordnance dated March 1829. 

The Admiralty and the East India Company ultimately requested Dent's services due to his reputation for accuracy. In August, 1829, Dent Marine Chronometer No. 114 won the First Premium Award at the Seventh Annual Trial of Chronometers. In 1830, Dent became a partner in the firm of John Roger Arnold of 84 Strand

Dent reports that chronometer No. 633 was given to Captain FitzRoy on board HMS Beagle in 1831 with 21 other chronometers in an article titled Hints on Chronometers that appeared in Nautical Magazine in February 1833. 

On 30 September 1840, the partnership of Arnold and Dent came to an end. The business E. J. Dent, London, opened its doors at 82 Strand on October 1, 1840.

Dent filed a patent for "Certain Improvements in Chronometers and Other Timekeepers" on March 21, 184. In January 1843, Dent opened his second premises, at 33 Cockspur Street, just off Trafalgar Square. The same year production and sale of Dent's Dipleidoscope started.

The Astronomer Royal, Sir George Airy, suggested Dent to create a sizeable clock for the new Royal Exchange's tower.

Dent built a facility at Somerset Wharf, Strand, to manufacture this outstanding clock, which was placed in 1844. He was awarded the commission to build the Great Clock for the House of Parliament in Westminster in 1852, but passed away before the project was completed. 

References:

https://www.britannica.com/biography/Edward-John-Dent

https://www.britishmuseum.org/collection/term/BIOG68351

https://en.wikipedia.org/wiki/Edward_John_Dent

https://www.dentlondon.com/about/history.php

https://en.wikisource.org/wiki/Dictionary_of_National_Biography,_1885-1900/Dent,_Edward_John