1742

1742 (MDCCXLII) was a common year starting on Monday in the Gregorian calendar and a common year starting on Friday in the Julian calendar.

 Events 
January 24 – Charles VII Albert becomes Holy Roman Emperor.
February 16 – Spencer Compton, Earl of Wilmington, becomes Prime Minister of Great Britain.
February 18 – British attack La Guayra.
April 13 – The first performance of George Frideric Handel's oratorio Messiah, in Dublin.
 May 17 – Frederick the Great's army defeats Austrians in Chotusitz; later Austria cedes Silesia to Prussia
May 25 – A battle is fought at Sahay.
December 2 – The Pennsylvania Journal first appears in print.
Daniel le Pelley succeeds Nicolas le Pelley as Seigneur of Sark.
Kingdom of Prussia captures Jihlava.
Christian Goldbach formulates Goldbach's conjecture.
Colin Maclaurin publishes his Treatise on Fluxions.
Anders Celsius proposes the Celsius temperature scale.
James Bradley succeeds Edmond Halley as Astronomer Royal.
Henry Fielding publishes Joseph Andrews.
John Carteret, 2nd Lord Carteret becomes Secretary of State for the Northern Department.
Rigging of Chippenham by-election causes a political scandal.
William Pulteney created as 1st Earl of Bath.
Robert Walpole was elevated to the peerage and thus moved from the House of Commons to the House of Lords, (see February 16, above).
University of Erlangen is founded.
Lopukhina Conspiracy at the Russian court.
Molde in Norway becomes a city.
Construction starts on the Foundling Hospital in London.
Eisenach builds its Stadtschloss (city castle).
 In Peru, Juan Santon takes the name Atahualpa II and begins an ill-fated rebellion against the Spanish rule
 Afghan tribes unite as a monarchy.