Indeed, Dusan, the concept of the Trinity, while dominant today, wasn’t a given fact for all the Christian movements throughout history. After all, the questions of Christ’s nature and of Christ’s will are the main point of content in the first several centuries of the organized Christian religion, with some very interesting “battles” between the various movements. It’s just that the supporters of some of those movements/ideas (f.e. the Arians, being the most popular, also the ideas of Monothelitism, Monophysitism, Miaphysitism etc) didn’t gather enough political power and were eventually cast out as heresies by the more powerful movements (although some relics of them still exist, like the Miaphysite Armenians). Heck, the same could very well be said about the earliest church, right after Jesus’ times – the contradictions between Paul and James are relatively well known and if Paul hadn’t won, Christianity today would have been horribly different (and probably a very minor footnote in history, considering it’s Paul who opened it from a “Jews-only” club to “free for gentiles” as well).