"at the centre of the room lay a catafalque, a doomed, ominous bier of Renaissance workmanship"

A catafalque is a raised platform used to support the coffin, casket or body of a deceased person.  They tend to be most recognisable these days when a monarch or leader has died and lies in state for a time.  A famous Renaissance catafalque was the one designed for Michaelangelo's funeral by his fellow artists in 1564.