The Walled City of Carcassonne

Defensive walls have been built around cities since before Joshua fought the battle of Jericho. For literally thousands of years, if you wanted to protect a collection of assets (people, livestock, intellectual property, real estate, etc.), you put them in a city and built a fortified wall. If you were really serious about protecting your investment, you added a moat or ditch or other obstacle and, where possible, built on the high ground.

This method of defense worked great… right up to the 7th or 8th Century in China and the 11th through the 13th Centuries in Europe. That’s when the gunpowder-powered cannon made defensive walls useless. What good is a wall with a big hole in it?

If you were a city owner, city builder or city dweller in 13th century Europe, you might have thought that the best way to survive was to scatter your people (or livestock, intellectual property, real estate, etc.) so that it would not be susceptible to invasion from cannon-wielding invaders. After all, a cannon (especially a 13th Century cannon) capable of blowing a hole in a city wall is big and the army that has to move it must stay with it to protect it. Scattering about the countryside would protect you from a serious army that used a big cannon to enter a city and pillage it.

The funny thing is… that’s not what happened. The technology (the gunpowder-powered cannon) forced changes in military strategy, political strategy and consumer behavior. It also had a profound impact on the “doing of life” for both the aristocracy and the proletariat. Cities did not get smaller – they got bigger. Since cities no longer needed walls, all kinds of things were empowered to change. Land ownership, land use, commerce, human interaction, the distance between the “country” and the “city,” even site selection for town centers adapted to the new paradigm.

Learning From the Past

So what can we learn from the relationship between walled cities and gunpowder?

There are myriad lessons, but today I’m interested in Cyber-security, Cloud Storage and Firewalls. There are several parallels one can draw with respect to the use of walls to guard things. A wall can keep primitive invaders at bay for a while… but siege engines are the “anti-wall” and the arms race can go either way on any given day.

Which begs for the question: How should one defend a collection of bits in the 21st Century? If walls can be breached with “virtual” gunpowder-powered weapons, how should we think about defense in an open environment?

Is it possible to defend a collection of bits when the bits are openly available to everyone on the Internet? If it is, are there strategic lessons can be learned from urban planners over the past millennium?

I think there are. But I want to know what you think.

A Homework Assignment for You

First, pretend that a highly protected collections of bits (like iTunes movies or music or CAD/CAM B1 Bomber Plans) are defended by “virtual” ancient city walls.

Now pretend that Anonymous or some other hactivist group has a “virtual” gunpowder-powered cannon and will have no trouble blowing a hole in it.

Now pretend that the IP stored behind the city walls wants to spread out, get bigger and become more valuable.

How will it happen? Email your ideas to me at or post something on my FB wall or follow me @shellypalmer and tweet me your thoughts.

About Shelly Palmer

Shelly Palmer is the Professor of Advanced Media in Residence at Syracuse University’s S.I. Newhouse School of Public Communications and CEO of The Palmer Group, a consulting practice that helps Fortune 500 companies with technology, media and marketing. Named LinkedIn’s “Top Voice in Technology,” he covers tech and business for Good Day New York, is a regular commentator on CNN and writes a popular daily business blog. He's a bestselling author, and the creator of the popular, free online course, Generative AI for Execs. Follow @shellypalmer or visit



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