That doesn’t change anything. The 10th century is still 1019 years before this year. Just like 20th century fox means 1901-2000. I get what you are trying to say, but language is used to convey ideas. If the words you use to convey your idea doesn’t match up to what the rest of the world thinks, then it is you who is wrong not the rest of the world. To argue against it is to argue against modern conventions. Example: What year is it?

If you give any other answer than 2019 then you are wrong.

Same thing for... when was the 10th century?

Another great example is the imperial system. Just because the USA uses miles doesn’t mean they are right when writing down their units in miles. Every true scientist knows it should be kilometers and makes fun of the individual who used miles. Why? Because the majority of Earth uses kilometers not miles.