let a city rebel?

[godsakes]

You have, I presume, destroyed all but the essential Roman buildings and built Iberian ones instead? That way you avoid culture difficulty.

i generally leave building which still give my faction a bonus - but i noticed some of the high end temples in italy didn't give me any (presumably above the level the Luso can build) so i've got rid of those

[Macilrille]

i generally leave building which still give my faction a bonus - but i noticed some of the high end temples in italy didn't give me any (presumably above the level the Luso can build) so i've got rid of those

All buildings not of your culture and that you cannot build/expand gives you a culture penalty to public order. Unless they provide you with a huge bonus, raze them.