Afternoon.

Bit of a poser here for those familiar with the expanding background of the Horus Heresy.

As per the title - just when did Horus lose?

Now the obvious answer 'when the Emperor mind-bulleted him to death' isn't what I'm looking for.

Instead, I'm wanting to explore the decisions made during the conflict as a whole - so really from the start of the Isstvan cleansing, right up to the final moments on his Battlebarge.

Quick comparison? World War 2. The war wasn't won when Berlin was taken - instead, that was just the final event of a long chain of disasters. Some feel it was when they opened up the Eastern Front, and provoked Russia. Others argue it was The Battle of Britain, in which the German war machine was dealt it's first serious defeat.

So that sort of thing. What was Horus' first blunder? Was it one of his allies who cost him the initiative required to strike before the rest of the Imperium could gird itself - or was it his own hubris?

Right. Off you go