The ancient city

My wife and I were watching a documentary on the Smithsonian channel called Fortress: Britain, which reviewed the ways that ancient castles and fortresses were built and the way cities rose up in their precincts. A few interesting details stood out. One was that the ancient city-fortress, which was always walled, was typically built on a hill. The reason was that it was harder for invaders and marauders to lay siege to a hilltop fortress, because they had the extra burden of trying to attack uphill. Not easy. Another interesting idea was that invaders often would dig tunnels under ancient city-fortresses to get in, since the hill setting and walls made it very hard to go over. Invaders would dig tunnels under the city walls and the weight of the city walls would cause the tunnels to collapse, taking the walls down with them. (This is the original meaning of the verb to undermine.) So, a development in ancient fortification was to build your fortress-castle on top of solid rock so that no one could dig under it. With every new development in offensive war, a defense was invented. All very interesting.

Then, coincidentally, a couple of days later in my reading I came across two passages from scripture in which Jesus describes the Church. In the first, he describes the church as a shining city on a hill. (Usually, one reads this and takes it to mean that the Church will be bright and on high, a beacon to the world.) In the second, he says to Peter that "on this rock I will build my church." (I usually took this to mean that the church had a solid foundation.) He also, in the latter passage, describes Peter as one who holds the keys, which is also evocative. Usually, the idea of the keys is interpreted to mean Peter is the steward who has the keys to all the rooms of the master's house.

But I've been wondering if the keys might also be an image of the keys to the city, the keys that open and lock the gate. That seems more in keeping with the following lines about what he binds on earth is bound in heaven, etc. And what if the Church is a city on a hill because that's where you build cities when you know you need to defend them? And what if you build your Church on rock so it can't be undermined, literally and figuratively?

All these images add up to an image of a Church built on a rock foundation so its enemies can't undermine it and bring down its walls, a Church on a hill, the ideal location for a fortress against hostile invaders, a church within walls where the apostle(s) hold(s) the keys to the gate.

The images, then, that Jesus uses to describe his Church are of a Church always under attack. Too much?

I think your observations are spot on. We've had this discussion before, where, to really understand scripture, it behhoves one to know the context in which it was written.

Things that were fundamental to survival centuries ago have fallen out of modern popular consciousness. The analogy of building a fortress on rock would have been well understood 2000 years ago.

Following up on Peter and his keys; the other way to defeat a fortress was from within.

The story of Troy and the Trogan Horse is believed to have been alegory for a spy within the fortress. The Athenians had a spy planted within Troy that unlocked a gate in the early morning hours. The Athenians slipped in through the unlocked gate in the early morning hours and fell upon the unsuspecting Trojans.

To protect a fortress it was just as important to know who was allowed to unlock a gate. If you think about Apolstolic Tradition and the Magisterium, it is the same thing.

I think I've read something somewhere about the keys being a reference to Isaiah and the steward having keys to the city,not just the house. I'll have to see if I can dig that up.