(Northumberland) was once called Moncaster, from the monks who
settled there in Anglo-Saxon times; it was called Newcastle from the
castle built there by Robert, son of the Conqueror, in 1080, to defend
the neighbourhood from the Scots.
(Staffordshire) is so called from the new castle built to supply
the place of an older one which stood at Chesterton-under-Line, about
two miles distant.
Carry coals to Newcastle.
A work of supererogation, Newcastle being the great seat of coals.
The Latins have “Aquam mari infundere” (“To pour water into the
sea”); “Sidera caelo addere” (“To add stars to the sky”); “Noctuas Athenas” (“To carry owls to Athens,” which abounds in
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894