Do u know that the presence of Syrian army in Lebanon was to benefit & protect Israel from the PLO fighters?

This is all news to me. I heard a completely different version. Funny how a sworn enemy of Israel would be doing its bidding or am I missing the meaning. It certainly wouldn't surprise me if the Syrians had a beef with the PLO and drove them out. I just find it had to believe they had the interest of Israel in mind when they did it?