We had a rather well planned multidisciplinary scheme of work where History and RE complemented and intertwined with other subjects.
For example, we'd just completed Judaism and Early Christianity in RE when we were studying the end of the Roman Empire. As we were at the end of the Dark Ages, we were studying Islam in RE (with Art teachers joining classes on Islamic Art). By the time we were past Domesday and onto the Crusades, we knew a lot more from RS & Art than we would have done without them. We'd also started a significant proportion of algebraic work in Maths and Physics/Science and knew that it wasn't something invented by Europeans - Biology/Medicine and Chemistry both had topics that intertwined - using Da Vinci's sketches, chemical reactions and alchemy, Astronomy and Galileo...
We had historical Antisemitism during the Medieval Period and the Renaissance. Once we got into the Tudors, the Dissolution of the Monasteries and the Elizabethan Era, we were also covering South America in Geography, so that when we got to exploration of the New World, we could link knowledge from History, Art (drawing all those bloody peppers and tomatoes), RE, etc. And Music covered a lot of post Renaissance history, religion and political thought.
When covering modern history (as per specification 1830-Present Day), we were looking at slavery, colonialism, the Race for Africa and the consequences, all also integrated into RE, Music, Geography, English...
Throughout, we also had lessons upon identifying bias, politics, What Could They Gain From Saying This? Identifying fakes and lies was linked into interrogating data to see if the claims were substantiated by facts - how changing scales on graphs in Maths created different impressions.
We covered the use of biological/chemical warfare from dumping plague victims' bodies, the devastating impact of smallpox, the atrocities committed against native Americans during colonialism, knew that concentration camps were not a German invention and that famine was not always caused by bad weather, but could also be used as a weapon of war.
Considering it was supposed to be the worst school in town (and I don't think they were far wrong), it had a huge amount of cooperation and planning to ensure we had a broad and consistent body of knowledge and, very importantly, a bloody good bullshit detector.
We had a Deputy Head in charge of the timetables and lesson schemes who taught multiple subjects himself and always, always wanted us to understand, to question, to link together knowledge from lessons for.
And then the National Curriculum came in after I left.