"The memento mori motifs that figured in the city's mosaics...took on a new intensity of meaning" for Pompeians in the AD 70's, according to Pompeii: The Living City by Alex Butterworth and Ray Laurence. Earth tremors followed a devastating 62 AD quake and Vesuvius loomed over the landscape. With a heightened awareness of their own mortality, Pompeians often used skulls and skeletons for decorative effect.