II.   Sovereign

Mean Time, also known as Greenwich Mean Time (GMT), also known as Coordinate Universal Time is an ecclesiastical and legal form of enclosure of time under the “law of the (holy) sea” whereby the mean solar time at the Royal Observatory at Greenwich Hospital in Greenwich, London is considered the global time standard since the end of the 19th Century.

The concept of basing time relative to Greenwich Mean Time (GMT) was first adopted by the Great Western Railway of Great Britain in the schedule of its times from 1840:

(i) Great Britain recognized the superiority of the Roman Catholic Church in respect of the Gregorian Calendar instituted by Pope Gregory XIII (1572-1585) (and its Canon Laws) by 1751 through (24 Geo.2 c.23) and in 1752 (25 Geo.2 c.30); and

(ii) Greenwich Mean Time (GMT) was then adopted by the whole railways and Post Offices of the United Kingdom from 1847. The first reference to Greenwich Mean Time as the standard time system for all the United Kingdom, Dominions and Colonies was from 1880 and the Statutes (Definition of Time) Act (43 & 44 Vict. c. 9); and

(ii) North American railroads introduced (zoned) standard time there on 1883-11-18 Sun; most larger US towns were using it by October 1884; legalized by US Act of Congress in 1918; and

(iii) Ireland adopted Greenwich Mean Time in 1916, supplanting Dublin Mean Time; and

(iv) In 1925 at the 2nd International Astronomical Union Conference in Cambridge England, the Greenwich Mean Time (GMT) was proposed to be changed to be known as the Universal Time (UT) globally. This was formally adopted and agreed by 1935 in Paris; and

(v) From 1st January 1972, a new unit of time called the Coordinated Universal Time (UTC) based closely on GMT but using atomic clocks was first introduced. The difference between UTC and UT (GMT) is marginal.