The castle represented strategy consulting, besieged by the Big Four, who were using transformation to push up the value chain—or, in my analogy, demolish the outer walls of Fortress Strategy. At the same time, the inhabitants of the castle (the traditional strategy players) were eyeing the swathes of transformation work being undertaken just outside their fortress walls. Some hunkered down in their inner sanctums and missed the opportunity to capture a significant share of the transformation market. Others were quick to launch sorties, running out from their castle under the cloak of darkness to grab what work they could and take it back inside, inadvertently weakening the walls themselves (firms going out created spaces for the Big Four to go in).

I’m mentioning all this because I think today’s competitive landscape is different—and it is changing still. The fortress is no longer about strategy, and the landscape is no longer just about digital transformation.

The castle is now inhabited by firms I’d describe as “emperors” (the Big Four, the MBB, Accenture, for example). Like Roman emperors, their rule extends to the farthest reaches, and they command unprecedented resources. You can walk round the world and still be in markets that these firms address; you can move from sector to sector and still find these firms have the experience to help. But also like the Roman emperors, these firms face challenges: Large empires were incredibly difficult to run; they can be attacked on many fronts at once, making it difficult to allocate resources to the right battles at the right time; and complexity and scale meant that the ability to adapt slowed. The result? Gothic hordes that periodically swept across parts of Europe, culminating in the Visigoths’ sacking of Rome itself in 410 CE. Today, “emperor” firms are facing their own “barbarian” competitors: new or re-positioned firms that have spent the last few years honing their fighting skills out of sight of the fortress lookouts. The latter are starting to show up now, however. Barbarian firms are smaller but are often more active in the markets they’re targeting. What they lack in scale, they may make up for in innovation.

In any research we do that asks a broad-spectrum question about who clients might be choosing to work with in a given field, the results highlight two points about the emperor/barbarian landscape.

Firstly, while the barbarians may not be at the gates, they’re certainly on clients’ radars, and often in unexpected places. Clients now are buying different services: It used to be that a CHRO would buy HR-related services, a tax specialist would buy tax services, a CMO, creative services, and so on. But the complexity of the issues clients need to address and the multidisciplinary nature of the solutions they require mean that—for example—technology services are being bought by strategy directors, while CIOs are buying strategy support. Some clients may choose to work with firms they’ve worked with before but in different areas, trusting them to have the necessary expertise, but others are looking for something new. Non-CHROs buying HR-related support don’t tend to go to the specialist HR firms their colleagues have relied on because they think they’re buying something different (they’re more likely to describe their needs around people than around HR). All this paves the way for very different firms to be in the mix when clients are deciding who to invite to tender.

Secondly, the reasons for hiring a barbarian firm are very different to hiring an emperor. The competitive advantage of emperors is their brand and scale: There are certain types of work (high-profile, large) that only an emperor firm can do. Barbarians are seen to be strong in different areas: their ability to move quickly, to be more responsive to client needs, and to make better use of technology in delivering their services. These differences mean that clients are interested in trying the barbarians out, not on the biggest, highest-risk projects, but on mid-sized ones. Clients are, in effect, starting to dismantle the outer wall of the emperors’ fortress. Stone by stone, they’re slowly but surely handing work over to the barbarians.

None of this will bring the emperors’ fortress down overnight: This is a long-term war of attrition. But it may still pay the emperors to post more outlooks and to keep an eye on the strength of the walls they stand on.