We don't have much information on this, but it seems that Bosnians did have a separate ethnic identity.

They referred to themselves as ''Bosnjani''.

The problem comes when you take into account, that medieval kingdoms didn't have our notions of nationality, so it gets really tricky to even understand the makeup let alone to explain it.

Or did the population just consider themselves ethnically Serb or Croatian depending on their religion

Some did, most did not.

Bosnia did have its own church, '' The Bosnian Church'' and it was neither Orthodox nor Catholic, in fact the Vatican had proclaimed Bosnia as a ''Heretical land''.

There was a Catholic and Orthodox presence in Bosnia, but it never had much power or influence, neither did the Bosnian church. This is one of the reasons as to why so many Bosnians converted to Islam, they never had strong Christian roots to begin with.

However, if we look at old historical documents referring to Bosnia, it was never described as ''Croatian or Serbian land''.

Well, there is one document that says that Bosnia is ''A land where the Serbs dwell'', but that was most likely referring to the fact that Bosnia was a vassal to Serbia at that time, so the Serbs ruled. But don't let this one document give you the wrong impression! Many have twisted its meaning to push propaganda.

but did they have an ethnic identity,

They had an ethnic identity, the same way other kingdoms did.