These prophets were talking about their own day, their own time. They were intent on achieving change within their own community.
When the expectations of the first and second century Christians failed and they were being taunted by the Jews, the Christian writers distorted the immediate meaning of Hebrew (OT) Scriptures to make them appear as if they were intended to apply to their murdered leader, Yeshua.
Learn the lesson taught by history: throughout the centuries, people have continually applied such statements to their own times, and they have a score of a big fat zero. Paul thought it was imminent ("we who are still alive", was talking to people about their time). In time to come, you too will wake up.
In answer to your question: Armagedon (Mount of Assembly) is the name of a place (you will know of its importance to Josiah). Armagedon is not the name of any battle. Since there is no such Mount, the person who wrote these words had a symbolism in mind that drew on his Hebrew/Jewish background.
Doug