Giuliano Medici, the younger brother of Lorenzo, was nursing a bad knee on Easter Day 1478 and had to be helped to the cathedral—by the very men who were plotting to kill him and his brother during mass. The assassins, members and supporters of the Pazzi family, banking rivals of the Medici, awaited their signal. As worshipers bowed their heads at the elevation of the host, Giuliano was brutally stabbed. Lorenzo escaped to the sacristy, remaining there while the Pazzi partisans attempted to seize the government. They soon failed, however, and Lorenzo resumed control.
The murder of Giuliano shocked Florence, and a number of portraits were ordered for public display to serve both as memorials and as warnings to other plotters. Botticelli's painting may have been the prototype for others, and lent symbolic gravity to Guiliano’s passing, showing him as an icon, almost a saint. The open window and mourning dove were familiar symbols of death, alluding to the flight of the soul and the deceased's passage to the afterlife. Some scholars, noting the lowered eyelids, suggest this portrait was painted posthumously from a death mask.