How about the Norman Invasion of 1066?
When the Normans, who spoke a dialect of Old French, ruled over England, they changed the face of English. Over the ensuing two centuries, thousands of Old French words entered English. Because the ruling class spoke Old French, that set of vocabulary became synonymous with the elite. Everyone else used Old English. During this period, England's society was diglossic: one community, two language sets with distinct social spheres. Today, English-speakers pick and choose from the different word sets—Latinate (largely Old French borrowings) and Germanic (mostly Old English-derived words)—depending on the occasion. Although English is no longer in a diglossic relationship with another language, the Norman-era diglossia remains reflected in the way we choose and mix vocabulary. In informal chat, for example, we might go on to ask something, but in formal speech we’d proceed to inquire. There are hundreds of such pairs: match/correspond, mean/intend, see/perceive,speak/converse. Most of us choose one or the other without even thinking about the history behind the split. Germanic words are often described as earthier, simpler, and friendlier. Latinate vocabulary, on the other hand, is lofty and elite. It’s amazing that nine hundred years later, the social and political structure of 12th-century England still affects how we think about and use English.Robert Archambeau adds his thoughts:
In any given period, most people are unaware of the presence of the past in their everyday life: it is part of the darkness of their era, the darkness that only the true contemporary sees. This isn’t an obscure point, though it may sound like one. Almost no speakers of English, for example, give any thought to the fact that the words they speak are a living example of particular historical events. The Battle of Hastings in 1066 led to the domination of the Anglo-Saxons by a French speaking elite, and the language we speak was forged in that crucible of conquest, where French and Anglo-Saxon melted together, giving us the rich and redundant (Anglo-Saxon “underwater” and French-derived “submarine”) vocabulary we use. 1066 happens in every sentence spoken in English, it lives in every sentence, though the speakers of the language tend to have no notion of it whatsoever. And this lack of awareness, this darkness, means that most people don’t fully live vast portions of the things that live in them: that is, they don’t grasp, and never come into conscious contact with, the things that make them who they are.