To break the ice
(1) to relax a tense or formal atmosphere or social situation; (2) to make a start on some endeavor.
This came into general use, in sense (1), in English through Lord Byron’s “Don Juan” (1823) in the lines:
And your cold people [the British] are beyond all price,
When once you’ve broken their confounded ice.
The ice in question is metaphorically that on a river or lake in early spring. To break the ice would be to allow boats to pass, marking the beginning of the season’s activity after the winter freeze. In this way, this expression has been connected to the start of enterprise for abour 400 years.
Source: Fun-with-words.com
