Augustine gives an argument (City of God Book V chapter IX, among other places) that I've always had little patience with. Here is R.W. Dyson's translation of the City of God occurrence of it:
Moreover, even if a certain order of causes does exist in the mind of God, it does not follow that nothing is left to the free choice of our will. For our wills are themselves included in the order of the causes which is certain to God and contained within his foreknowledge. For the wills of men are causes of the deeds of men, and so He Who has foreseen the causes of all things cannot have been ignorant of our wills among those causes, since he foresaw them to be the causes of our deeds.
The reason I find such reasoning frustrating is because it comes across as if Augustine is trying to respond to the foreknowledge problem by saying that God foreknows our free choices, and if God knows our free choices, and God can't know something false, then they must be true. So foreknowdge of free choices actually establishes them as free rather than undermining it. The problem with such an argument is that it's question-begging. The opponent of foreknowledge will insist that God can't foreknow a free choice. So the very assumption of the argument is what the argument is trying to prove.
As I re-read the sections of City of God that I taught this semester in Dyson's translation (now that I've finally managed to get a copy), it occurred to me that Augustine might actually be doing something different in this text, something much less problematic. It looks to me as if what he's saying is that, even if there is this order of causes leading up to our wills, that's compatible with our choices being free, and then he gives a reason. The reason is that our wills are the causes of our actions. God's foreseeing of what we choose is God's foreseeing of our causing our actions. It's not God foreseeing our freedom that makes freedom compatible with foreknowledge, as the bad argument above has it. It's that God's foreseeing our freedom is God's foreseeing our own causing of our actions. Such causing is what explains our freedom.
Thus Augustine is making the Stoic point that our choices do happen even if there are causes of them that God can see ahead of time, and it's that they happen as choices that makes them free. Augustine does later distinguish his view from the Stoic position, but at this point he seems to be giving basically the same argument they give for compatibilism about being caused to do something and being free in doing it.
[Completely as an aside, what is going on with Dyson's capitalization in that passage? He capitalizes not just the personal pronoun but even the relative pronoun when it refers to God, but then he leaves even the personal pronoun in lower case in the very net clause. It's almost as bad as some Bible translations when trying to deal with psalms that don't clearly refer to just a messanic figure who thus to a Christian refers to Christ.]