Might be somewhat controversial, and I believe older historical debates are safer grounds, but what about how much blame Hirohito deserves for Japan's entry into WW2? Two views exist:
Hirohito, as per ancient Japanese imperial tradition, was a revered figurehead ruler. As such he was not expected to influence government policy directly, but rather serve ...
If you're looking for something where the evidence is undisputed, but the interpretation varies, a good choice would be the starting date of World War II. The three mainstream dates:
July 7, 1937, with the start of the Second Sino-Japanese War.
September 1, 1939, with the Invasion of Poland.
December 7, 1941, when the attacks on Pearl Harbor, the ...
OK, I'm not a historian, but I like history. How about the origin of the Sphinx? I think some of the recent theories (e.g. Colin Reader https://www.dailygrail.com/2014/06/did-the-great-sphinx-of-egypt-originally-have-a-different-head/) make a lot of sense, but the the traditional Egyptologists reject his ideas.
The classic question for this age group is the use of atomic weapons in the Pacific War. Was it necessary? Was it just? How does the ending compare with the foreign policy aims of the US prior to the raid on Pearl Harbor, and afterwards? To what degree were decisions made based on moral grounds, as opposed to the mere existence of the weapon driving its use.
Who first discovered America?
Common ‘wisdom’ in the US is that it was Christopher Columbus, and the public schools in the US generally say exactly nothing more.
Prior to that though, the Norse peoples colonized Greenland (around 980 CE), and there was a short-lived Norse colony established in what is now Newfoundland (specific people to look up are Leif ...
Factors I'm using
Preferably, it should be about some subject that they have already learned
If possible, there should be only two big theories (and maybe a few alternatives with minority support), with the debate being mostly about which of them fits the available data better
It shouldn't be too politicized (cuts off most of the "was X real?" ...
For what it's worth, I think you should flesh out some of your discussion on this topic with things that people were once bitterly divided about but which were later resolved in various ways. As you and om noted, the historicity of Troy (resolved in favor) alongside the Romans' Aeneid myths and England's legends on Brutus and the Matter of Britain (resolved ...
Did Marco Polo Really Go to China?
There are two major theories/groupings about Marco Polo's claims and publications that he travelled to China with his uncles and lived there for many years.
It really happened basically as he claimed, or
He actually was in Turkey, Persia or some other midpoint most of that time and his information about China was based on ...
Whether there was a historical nation called Palestine (anytime from circa 1000 BC to to early 20th Century). Partly, this swings on whether one should read sketchy ancient records of Philistines/Palistina/Walistina/Falistina/Palastin as identical with Palestine or not (as well as whether they indicate a country or an ethnicity, whether the concept of ...
How about the Late Bronze Age collapse?
It would fit nicely into the background you provided under point three and I think could be explained at an age-appropriate level with lots of somewhat commonly known examples.
The different theories (eg. the mysterious "sea peoples") should be quite exciting to discuss.
On a lighter note (compared to the suggestions in other answers), possibly more suited to 12-year olds and with no possible covert political/religious/etc message, try:
Did Robin Hood exist?
Did King Arthur exist?
The Kennedy assassination would seem a prime example of disputed history, as would the role of the Mafia in John Kennedy's election as President.
The Rosenberg trial would be another.
Whether the United States was properly informed of the Pearl Harbor attacks is still a question of some debate.
The Vela incident was a possible nuclear weapon test in the ...
The Anglo-Saxon invasion/settlement of Britain?
It's agreed that in the space of a few centuries, most of Britain went from being:
mixed Christian/Pagan in religion
mostly Celtic-speaking by language
Romanized in culture
Germanic Pagan in religion
Germanic by culture
But how this change took place—whether this was a mass ...
I think Jesus of Nazareth can be a proper candidate for this question. Quoting verbatim from Wikipedia:
There is widespread disagreement among scholars on the historicity of specific episodes described in the biblical accounts of Jesus, the details of the life of Jesus mentioned in the gospel narratives, and on the meaning of his teachings. Many scholars ...
You can start with the Schliemann discovery, the so-called Priam's treasure, the realization that there were different layers, pinpointing Troy VII as probable Homeric Troy.
Fits into the history they know.
Unlikely to let modern passions hide the lesson you want to drive home.
Well it's a pity that the only civil war your class is aware of is a fictional one between superheroes, because otherwise the US civil war fits your criteria perfectly I think.
My personal opinion and the opinion of a lot of historians today is that the Confederacy fought to preserve the evil institution of slavery, however there were and still are a lot of ...
I recently read that some years ago, some scholars formed the view that there never was an Catharic heresy, much less a Catharic religion, not even a separate Catharic "church" organisation. All that there (supposedly) was were some major misunderstandings within Christianity. E.g. that most of this article is mistaken. This might be a good example ...
The short answer to your question is: YES, they did.
Herodotus and Josephus both reference and footnote many more ancient historians and their work. Rulers throughout the eastern Mediterranean are among them.
Unfortunately, much of it has been lost to history in such events as conquest/destruction among nations and tragedies such as the fire that destroyed ...