Aborted Krewo - A Timeline idea
The death of Jadwiga
Jogaila's Russian mother Uliana of Tver urged him to marry Sofia, daughter of Prince Dmitri of Moscow, who required him first to convert to Orthodoxy. That option, however, was unlikely to halt the crusades against Lithuania by the Teutonic Knights, who regarded Orthodox Christians as schismatics and little better than heathens. Jogaila chose therefore to accept a Polish proposal to become a Catholic and marry the eleven-year-old Queen Jadwiga of Poland. The nobles of Malopolska made this offer to Jogaila for many reasons. They wanted to neutralize the dangers posed by Lithuania itself and to secure the fertile territories of Galicia–Volhynia. The Polish nobles saw the offer as an opportunity for increasing their privileges and avoiding Austrian influence, brought by Jadwiga's previous fiancé William, Duke of Austria.
On August 14 1385 in Kreva Castle, Jogaila confirmed his prenuptial promises in the Union of Krewo (Union of Kreva). The promises included the adoption of Christianity, repatriation of lands "stolen" from Poland by its neighbours, and terras suas Lithuaniae et Russiae Coronae Regni Poloniae perpetuo applicare, a clause interpreted by historians to mean anything from a personal union between Lithuania and Poland to a complete incorporation of Lithuania into Poland.The agreement at Kreva has been described both as far-sighted and as a desperate gamble.
However, Jadwiga died on December 1385 due to suspicious circumstances some people believed that it is Siemowit of Plock and Wladyslaw of Opole, the Piast Faction that ordered the death or the Bohemian Faction led by Sigismund of Luxembourg, the heir of Casimir III that caused the death and so the marriage between Jogaila and Jadwiga did not happen.