What is biblical typology, and how did the Church Fathers use it?

Biblical typology is the interpretive method that reads persons, events, and institutions in the Old Testament as divinely arranged anticipations of Christ and the Church. The method is not allegory in the speculative sense — it is grounded in the conviction that one Author coordinates both Testaments so that the earlier prefigures the later. Augustine stated its orienting rule: when we hear a Psalm, our whole design is to see Christ there — and in the Church, his body. Origen applied the same principle to narrative, arguing that when Israel crossed the Red Sea, it was baptism's type written in history; the letter is real, but it points beyond itself. The Fathers used typology for three interlocking purposes: to demonstrate Old Testament continuity against Marcionite claims that the Creator God differed from the Redeemer, to open the sacraments as fulfillments of Israel's ritual life, and to train the spiritual senses of new converts to read all Scripture as pointing to Christ. Jerome's discipline note remains: typological reading requires guidance, lest the interpreter project meanings rather than receive them. Ambrose extended the method liturgically, teaching that every baptismal mystery has its root in an Old Testament type — the crossing of the Jordan, the pillar of cloud, the manna — so that the new Christian enters a tradition of reading as well as a rite.