Is it permissible to teach the history of ancient civilizations and their beliefs, and to teach historical events that may include accusations and slanders against Islamic factions? And is mentioning the bad actions of historical figures considered backbiting?

Formal education today is an urgent necessity. Given the presence of Sharia contraventions in schools and curricula, especially in the subject of history, enjoining good and forbidding evil becomes an obligation according to one's capacity. A teacher cannot change the curricula, but they can denounce it in their heart, and alert students to Sharia and scientific errors in a way that does not harm them, while making them understand that what is in the curricula is what is required for exams. Allah does not burden a soul beyond its capacity, and it is obligatory to spread justice and remove oppression as much as possible. A teacher must strive for reform as much as they can, and denounce whatever wrongs are possible, clarifying the truth concerning them, especially regarding matters of creed and the fundamentals of religion. As for what they are unable to do or what would lead to a greater harm, Allah does not burden a soul beyond its capacity.