In the right conditions an island campaign allows for anachronisms. The trick is, the island or archipelago has to be relatively isolated. Not impossible to reach, just hard. As a result matters tend to lag behind the mainland technologically.
An extreme example is the island of Tasmania. Before the British colonization of the island the natives had lost much of the primitive technology their Australian ancestors had owned. They simply didn't have the people necessary to keep certain traditions alive. When the last person who knew how to do something died without passing his knowledge on to another, the technology died with him.
When communications with the outside world are good to excellent the situation can be reversed. Crete in the ancient world, and Britain more recently. Both were able through trade to gain much from the rest of the world. Combined with an early unification under one ruler this gave them an advantage in many areas. Advantages they used well. But this sort of thing should be resevered to island nations with a strong maritime technology and tradition.
An extreme example is the island of Tasmania. Before the British colonization of the island the natives had lost much of the primitive technology their Australian ancestors had owned. They simply didn't have the people necessary to keep certain traditions alive. When the last person who knew how to do something died without passing his knowledge on to another, the technology died with him.
When communications with the outside world are good to excellent the situation can be reversed. Crete in the ancient world, and Britain more recently. Both were able through trade to gain much from the rest of the world. Combined with an early unification under one ruler this gave them an advantage in many areas. Advantages they used well. But this sort of thing should be resevered to island nations with a strong maritime technology and tradition.