It's been five years since the release of the last Thief game, for Xbox and PC, and there was a four year gap in between that game and , so a long period of time in between games is not something new for the series.

Read the official press release announcing Thief 4 below:

Eidos-Montreal Announces Development of Newest Title in the Legendary Series

Eidos-Montreal is excited to unveil its previously secret second title in development at the studio, Thief(tm) 4, the next installment in the legendary series.