Since a long time, this message is getting circulated on social media and other platforms. If you have also believed in it and considered it as a knowledgeable information, then let us burst the bubble for you. A simple google search could reveal the truth behind this fake message but it is disappointing that even educated class is also a part of sharing these kind of unverified information.
As per google,
“’Sir’ derives from the honorific title sire, used in Spanish, Italian, French, German, and Swedish. Sire developed alongside the word seigneur, also used to refer to a feudal lord. Both derived from the Vulgar Latin senior, sire comes from the nominative case declension senior and seigneur, the accusative case declension seniōrem.”
“The form ‘Sir’ is first documented in English in 1297, as title of honour of a knight, and latterly a baronet, being a variant of sire, which was already used in English since at least c.1205 as a title placed before a name and denoting knighthood, and to address the (male) Sovereign since c.1225, with additional general senses of ‘father, male parent’ is from c.1250, and ‘important elderly man’ from 1362.”
Now, you know the real origin of Sir and its definitely not -” slave I remain”.