He died in 1148, while his year of birth is not known.

His specific years of birth and death are not known.

Only the last thirty years of his life are known to us.

The year of his birth is not known, however, it must have been around 1675.

She died before her husband, but the exact year is not known.

However, the 1960s were years known for the activism of various groups.

The years between 1985 and 1989 became known as the "die hard" era.

It was built in the 12th century, however the exact year is not known.

He eventually died in exile, but the year of his death is not known.

While the year of his death is well known, how he died and where are disputed.