u/Dialectrician

When you read about European imperialism in the Victorian era, you'll hear about European powers agreeing about "zones of influence" in e.g. Iran, with a map showing a Russian zone in the north and a British zone in Balochistan. Similar things for example in China.

But what did those entail in concrete terms? What did the treaty actually say? Could they put troops there, did they have some exclusive rights to invest, or did they just agree on the concept of influence and left it for later to figure out the details?