Question
Are we supposed to be doing Tenebrae still? When was it celebrated?
--Tenuous in Texas
Answer
When the Liturgy of the Hours was revised in 1974, Tenebrae was suppressed. Many religious orders had it as part of the their tradition for Holy Week and have continued the practice. It is similar to Morning or Evening Prayer today. Many customs were part of the service, such as taking candles away for certain prayers or psalms and making loud booms/noises.
Its origins come from solemn Morning Prayer celebrated according to the cathedral (parish) tradition during the Easter Triduum. At one time the Easter Vigil was pushed back earlier in the day on Holy Saturday as well as the Liturgy of the Hours. Therefore, so much so that Morning Prayer during the Triduum was celebrated the evening before: Tenebre.