Italics in the KJV

At least I think it’s the King James Version of the Bible - not having one in the house, I’m not totally sure, but when I attended church as a child I remember passages like “And then they went into the house of the Lord, and when they there sat they were filled with peace…” etc.

What do those italics mean? Why are they attached to such seemingly irrelevant words?

IIRC, they were words that were not in the actual Hebrew or Greek texts, but added by the KJ translators to make a smooth translation.

Thank you! 25 years of speculation wiped out with one post.

An earlier–and strangely, much longer–thread on this subject: