Republic of Austria
Who & why: the 15 May 1955 State Treaty ends a decade of four-power occupation in exchange for Austria's permanent, constitutionally enshrined neutrality — the last Allied troops leave that October. Neutrality kept Austria out of NATO and the Warsaw Pact alike throughout the Cold War; it joined the EU in 1995 and today treats the neutrality clause as flexible rather than absolute.
What it represents: the same red-white-red, first documented in 1230 under Duke Frederick II — a seal on a deed of 30 November 1230 — with a legend, which Austrian sources do not give, that Duke Leopold V's white surcoat was soaked crimson with blood at Acre in 1191 except where a sword-belt had shielded a white stripe. The state flag adds a federal eagle (single-headed, holding a hammer, sickle, and broken chains, crowned with a mural crown) that the plain civil flag shown here omits.
FOTW says the Flag Act passed by the Austrian parliament on 28 March 1984 put into effect the state flag (red-white-red with the arms) and its 2:3 ratio, and that the plain triband is the national flag and civil ensign. Wikipedia's infobox gives 1 May 1945 for the formal adoption and 28 March 1984 for the state flag, and 1230 for the origin of the design.
- Austria — Flags of the World (CRW Flags) compiled
- Flag of Austria — Wikipedia compiled
Not established: The date a plain red-white-red became Austria's flag again depends on which event is meant: 1945 (restoration), 1955 (this era's start) or 1984 (the Flag Act); the sources read do not give 1955. FOTW also notes the law does not specify the shade of red.