Kafka was unknown during his own lifetime, but he did not consider fame important.

Monumental construction on this scale is unknown elsewhere during this period.

Graziosa said that information from the book was unknown to the defense during the trial and might have helped his case.

Lucia stays relatively unknown during the course of the novel.

Physical attack isn't unknown during a game, and there are groups within the society which might want to harm you.

Field's compositions were very popular in the 19th century, but he became relatively unknown during the 20th as musical fashions changed.

Lovecraft was relatively unknown during his own time.

The fate of the Yellow Martians is unknown during this time period.

Piracy between competing English fishing fleets was not unknown during the period.

Hail and frost are not unknown specifically during winter.