Prompt
What was the name of the 1569 agreement that established the Polish-Lithuanian Commonwealth as a bi-confederate state?
Expected output
The Union of Lublin (1569).
| model | score | output |
|---|---|---|
| qwen/qwen3.8-max | 100% | The agreement was the **Union of Lublin** (1569). |
| gpt-5.5 | 100% | The 1569 agreement was the **Union of Lublin**. |
| claude-opus-5 | 60% | The agreement was the **Union of Lublin**, signed on 1 July 1569 in the city of Lublin during a session of the joint Sejm. **What it did:** - Merged the Kingdom of Poland (the "Crown") and the Grand Duchy of Lithuania into a single political entity, the Polish–Lithuanian Commonwealth (*Rzeczpospolita Obojga Narodów*, "Commonwealth of Both Nations") - Established a **shared** elected monarch (simultaneously King of Poland and Grand Duke of Lithuania), a common Sejm (parliament), a unified foreign policy, and a common currency - **Preserved separately** each partner's army, treasury, legal code, offices, and administration — which is why it is usually characterized as a *real union* or federation rather than a fully unitary state - Transferred Podlachia, Volhynia, Podolia, and the Kyiv region from Lithuanian to Polish Crown jurisdiction, a concession that caused considerable Lithuanian resentment **Background:** The union built on nearly two centuries of dynastic ties beginning with the Union of Krewo (1385) and the marriage of Jogaila and Jadwiga. The immediate pressures in 1569 were Lithuania's military strain in the Livonian War against Muscovy and the fact that Sigismund II Augustus, the last of the Jagiellons, had no heir — raising the question of what would hold the two realms together after his death. The arrangement lasted, with modifications, until the Constitution of 3 May 1791 moved toward a more unitary state, shortly before the Commonwealth was erased by the final partitions of 1793–1795. |