Christmas Truce of 1914

Like I always said of him: a smart man.

Not necessarily. At the time of his death, he could have been saved but he refused, saying that he did not 'believe in artificially extending life' or somesuch.

Hmm...

LOL. Irony in offering it to him then.

As far as I know, he aborred violence, even though he supported stopping Hitler, so he probably would not approve of the bloodshed.

• "Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius -- and a lot of courage -- to move in the opposite direction." ~Albert Einstein
• "Peace cannot be kept by force. It can only be achieved by understanding." ~ Albert Einstein

World War One was the apex of all that is wrong with imperialism: a disgusting conflict waged by princes and kings prepared to fight to the last drop of everyone else's blood. It's understandable that they took exception to the Christmas truce, as it would detract from the personal glory to be gained from sitting on their fat arses while the corpses of their young men piled up by the day.

You hit the nail on the head sir. The Main causes were
Militarism
Alliances
Imperialism
Nationalism