Wasted war effort?

[TLF]

A rival Civ (England) is on a separate Continent and there is a barbarian island off their coast with 1 city.

I went and took the city and built a second city.
The city I took is still listed as a barbarian (Phonetician) city and the people in my newly built city are clamoring to join England. Elizabeth will be made very happy.

The adventure now seems like a waste of time and effort.
Where's the upside?
There are horses, clams and iron on that island and I don't have horses and clams.
That island is also very furtile and I could get much commerce from the coastal tiles.
I guess I don't need horses though as I am at gunpowder and have been building cannons and Grenadiers.

 

[none]

Hard to say without a screen, but I'd use the island as a base to launch a large attack on the English Empire. That seems to be the upside, a safe harbour from which to launch an attack.

 

[LegionSteve]

I went and took the city and built a second city.
The city I took is still listed as a barbarian (Phonetician) city and the people in my newly built city are clamoring to join England. Elizabeth will be made very happy.

If you mean the pop-up message that tells you the people of your city want to join another civ, just ignore it. Or better yet, turn it off (advisor pop-ups or Sid's tips? I usually turn them both off).

I wouldn't liberate the city unless it is so surrounded by the English culture that it can't usefully produce anything. Then you might as well get rid of it and save yourself the maintenance. Or you really, really want the +1 or +2 'you liberated our cities' diplo bonus with Liz.

 

[s.bernbaum]

If the island is big enough to build two cities. It is big enough to keep. Ignore the nonsense about wanting to join England. The English culture influence cannot increase on the island due to the water in between, unless there is only one tile wide water in between. Once you build culture in the two cities, the English influence and the old barbarian culture will dwindle to naught.

The only way the English can take that island from you is with an army, so do build a good defense.