Why Did Jesus Come in 5 B.C.?

Consider two facts: God does not make arbitrary decisions and Christianity is a religion whose truths are rooted in and revealed through history. Assuming those claims are both true—and I have no doubts about either—it follows that the Father had a particular reason for sending the Son to earth circa 5 b.c. But if so, what was the reason for choosing that particular historical period? Could Jesus have come any sooner?

Recently, while reading the introduction to God and Governing—written by our own Roger Overton—I stumbled upon what may be a clue:

All Christian hope is placed in [Christ], in what he accomplished through death by Roman execution and in what lies ahead when he finally returns with a two-edged sword. As powerful as this message is, there is a sense in which the spreading of this message depends on a certain amount of social order. Theologian Harry Blamires explains, “In a jungle, where cannibals dine on missionary stew, were men prey bestially upon another, certain preliminary steps toward minimal restraint, hygiene, and the guarantee of continuing survival have to be taken before a prayer meeting can be arranged and the gospel proclaimed.” There must be some level of common civility in order for the love of Christ to be demonstrated and good news of his work explained, and this common civility often come through political social order.

Assuming that Blamires and Overton are correct and that a certain level of social order is necessary for the spread of the Gospel, was the first century the earliest period in which the conditions were ripe for the message to spread globally? While my knowledge of Jewish history is woefully inadequate, I assume that the coming of the Messiah and the fulfillment of his earthly ministry could have been carried out at an earlier time in the history of the Jewish people. But could the message of the Gospel have been carried to the Gentiles any sooner? Could the work documented in the Acts of the Apostles have been fulfilled without the social order established by the Roman Empire?

Christians have always recognized that the second coming of Christ would follow certain preconditions (though we may disagree whether or not all such conditions have already been met). Could it be that the Father had determined that an initial set of social and political preconditions were historically necessary before he sent his Son?