I've known since the first day who her father is.

She said the friends in the car had known one another since high school.

They had known one another since high school, some for even longer.

The two men had known each other since their school days.

They had known each other since the age of five.

He had known them both since all three were small children.

But I'd only known you since the beginning of summer.

However, its history is more well known since the 15th century.

The two had known each other since age 8 or 9.

We had known each other only a few months since my return.