The flag of Austria has three equal horizontal bands of red (top), white, and red. The Austrian flag is the second-oldest flag in use (which has been in use since 1230) after the Danish flag (which has been in use since 1219).

Duke Frederick II (1210-1246), the last of the Babenberg dynasty, who was nicknamed the “Quarrelsome” or the “Warlike”, designed a new coat of arms in red-white-red in the year 1230 in his attempt to become more independent from the Holy Roman Empire.

According to legend, the flag was invented by Duke Leopold V of Austria (1157–1194) as a consequence of his fighting during the Crusades. After a fierce battle, his white battle dress was completely drenched in blood. When he removed his belt, the cloth underneath was untouched by it, revealing the combination of red-white-red. So taken was he by this singular sight that he adopted the colours and scheme as his banner. Wikipedia