In 1940,-41 Germany was able to enlist the support of Roumania, Hungary (the latter at the expense of the former), and Bulgaria, in the Balkans. Yugoslavia initially signed on with Germany, then soon switched sides and declared herself for the Allies.
Why did Yugoslavia do this? I have a recollection of a difference of opinion between the minor (seventeen year old) king, and his uncle, the regent. Was this the real cause, or were one or both men pawns in a larger struggle?