City history
Founded by the Romans as Londinium, London evolved from an ancient commercial crossing on the Thames into the global origin of modern standard time.
Chapter one
Name origin
"Uncertain; likely derived from Brittonic *Londonjon, interpreted as place of the broad or flowing river."
Established by the Roman military around AD 47 as a bridgehead and trading settlement on the River Thames, adopting a pre-existing local Brittonic place or river name.
Uncertain Brittonic root, likely describing the River Thames.
Founded by the Romans after the invasion of AD 43, growing into a major commercial capital of Roman Britain.
London Trading Town (Old English Lunden plus wic).
An Anglo-Saxon merchant settlement located roughly a mile west of the old Roman walls around modern Aldwych and Covent Garden.
Fortified London Borough (Old English Lunden plus burh).
Reoccupied and re-fortified inside the ancient Roman walls by King Alfred the Great in 886 to defend against Viking attacks.
Evolved from Old English Lunden and Middle English orthography.
The modern spelling stabilized over time, replacing Old English Lunden and Anglo-Norman French Londres in local vernacular.
Chapter two
The Great Western Railway required all stations along its network to keep London Greenwich time, initiating the nationwide transition away from local solar times.
The Railway Clearing House recommended that Greenwich Mean Time be adopted across all British railway companies to synchronize nationwide train schedules.
Parliament passed the Statutes (Definition of Time) Act 1880, legally establishing Greenwich Mean Time as standard civil time across Great Britain.
To save energy during World War I, Parliament enacted the Summer Time Act 1916, advancing national clocks by one hour ahead of GMT during summer months.
During World War II, Great Britain maintained UTC+1 throughout winter and moved to UTC+2 during summer to maximize daylight for industrial production.
The UK launched a three-year trial keeping British Standard Time (UTC+1) year-round, temporarily discontinuing the seasonal fall clock change.
The United Kingdom aligned its daylight saving transitions with European Union standards, fixing changes to the last Sundays in March and October.
Chapter three
King Charles II founded the Royal Observatory at Greenwich to rectify astronomical tables and solve the longitude problem for safe ocean navigation.
The red time ball atop Flamsteed House dropped at 1:00 PM GMT for the first time, allowing mariners on the Thames to accurately set their marine chronometers.
The Great Clock at the Palace of Westminster went operational, utilizing Denison's double three-legged gravity escapement to achieve unprecedented public accuracy.
Delegates at the International Meridian Conference in Washington, D.C. designated Greenwich as the global Prime Meridian (0° longitude) and reference for international time.
The BBC began broadcasting six electronic pips from Greenwich Observatory across radio networks, allowing households to synchronize their clocks to official GMT.