Oukoku e Tsuzuku Michi - Chapter 570.6

In 2036, humankind steps foot on Mars for the first time.

There was a time where I was summoned to a different world. I spent more than a year as a Priestess from a different world. I fulfilled my role and decided to return to my original world. Before leaving, I confessed my feelings to my escort knight. And from there I was heartbroken. After returning to the original world for a year and half, I was summoned again. What? Apparently this time, nobody summoned me. I was sent out to a great extent and have a lost love. I cannot face anyone now! No one knows that I was a former Priestess and I can only quickly return to my original world. Even so, it does not seem to work out very well…

He lived from BC to the Middle Ages, from the Renaissance to the Industrial Revolution, and from Cyberpunk to the Interstellar Age. He has been a king and a prophet, a knight and a nobleman, a versatile artist, a genius inventor…
This is a four-thousand-year human epic——
“To us four thousand years from now:
“Is the world at peace? Is famine extinct? Can people touch the stars? How long is the human lifespan? How far is the boundary of the earth? Human…do you remember us?”
——Excavated from Earth Age Tenth Century BC, Solomon Prayer Book.

- Description from novelbuddy

In a world fraught with innumerable dangers where living day by day is a struggle, a young man from the modern age transmigrated into such a world, accompanied by a peculiar system made for assassination.