What does this Red Cross stand for in medieval Europe?

1. The Red Cross on a white background was originally the national flag of Genoa.

Crusader ships leaving Genoa during the Crusade were required to fly the Genoa flag when they left the port. Later, Richard's army returned to England with this flag, and the Red Cross on a white background gradually became the flag of England, that is, the flag of St. George.

3. Red Cross on white background, also known as "Red Cross" or "Geneva Cross". It shows the neutrality of the institutions and their medical personnel that protect battlefield rescue and prisoner of war relief between hostile parties in wartime. This is the symbol of the Red Cross.