Which happened earlier: Prague Astronomical Clock installed or Big Ben first chimes?

Question 1

Which happened earlier?

A Prague Astronomical Clock installed ✓ Earlier

B Big Ben first chimes

Prague Astronomical Clock installed (9 October 1410) came before Big Ben first chimes (11 July 1859)

Question 2

Which happened earlier?

A International Meridian Conference adopts Greenwich Meridian

B Royal Observatory Greenwich founded ✓ Earlier

Royal Observatory Greenwich founded (10 August 1675) came before International Meridian Conference adopts Greenwich Meridian (22 October 1884)

Question 3

Which happened earlier?

A First atomic clock built

B First quartz clock demonstrated ✓ Earlier

First quartz clock demonstrated (1 October 1927) came before First atomic clock built (1 January 1949)

Earlier #139