who is allowed to wear white when visiting the pope
Privilège du blanc A reigning Catholic queen or princess retains this privilege at the discretion of the Pope, by remaining a Catholic in good public standing, through marriage to another Catholic monarch, or simply by grant of the Pope at his dispensation.[citation needed] Catholic royalty may freely choose whether to exercise the privilege depending on the importance of occasion; if they don't, this is termed as "declining the privilege"[citation needed], and the fact of choosing to wear black garments at certain points of Papal audiences does not negate her privilege to be dressed in white.
White flag The first mention of the usage of white flags to surrender is made during the Eastern Han dynasty (AD 25â€“220). In the Roman Empire, the historian Cornelius Tacitus mentions a white flag of surrender in AD 109. Before that time, Roman armies would surrender by holding their shields above their heads.[1] The white flag was widely used in the Middle Ages in Western Europe to indicate an intent to surrender. The color white was used generally to indicate a person was exempt from combat; heralds bore white wands, prisoners or hostages captured in battle would attach a piece of white paper to their hat or helmet, and garrisons that had surrendered and been promised safe passage would carry white batons.[2]