Crusade in capital and not in capital

1. Does "also unexpectedly back in Russia" mean "it was not expected Russian artists like Marc Chagall or Natalia Goncharova create art-related artworks"?

2. Does here "crusade" mean simply "war"? If it was in capital (Crusade) it would mean the religious wars of Christians against Muslims, Yes?

3. Does "with God’s blessing" mean these paintings also depicted the mercy of god?

Context:

Russia maintained an official war art programme, but some expatriate artists, the Russian equivalents of Hartley in Berlin, capture the initial national response to the war. These creative people could not know the horrors to follow: mass killings and dislocations, broken homes, shattered families, and ultimately revolution and war combined. Marc Chagall, for example, found himself isolated in his home town of Vitebsk for the war’s duration, although Paris was now his home. He observed the conflict’s initial impact on his community in a series of moving drawings that focus on themes such as leave-taking. Natalia Goncharova, also unexpectedly back in Russia, responded immediately to events with a print series – Mystical Images of War (1914) – a rather medieval view of a crusade, with God’s blessing.