1725, Daniel Defoe, Everybody's Business is Nobody's Business:
The reason why I did not publish this book till the end of the last sessions of parliament was, because I did not care to interfere with more momentous affairs.
"It has been a momentous month, and I hope we shall all retain healthful recollections of it as long as we live."
1902, Joseph Conrad, chapter 3, in The End of the Tether:
What to the other parties was merely the sale of a ship was to him a momentous event involving a radically new view of existence.
1952 December, R. C. Riley, “By Rail to Kemp Town”, in Railway Magazine, page 835:
The last train ran on December 31, 1932, almost unnoticed, for it coincided with the running of the last steam passenger train down the main line from London to Brighton, a much more momentous event.
Natural selection is arguably the most momentous idea ever to occur to a human mind, because it — alone as far as we know — explains the elegant illusion of design that pervades the living kingdoms and explains, in passing, us.
