The siege of Weinsberg took place in 1140 in Weinsberg, in the modern state of Baden-Württemberg, Germany, which was then part of the Holy Roman Empire. The siege was a decisive battle between two dynasties, the Welfs and the Hohenstaufen. The Welfs for the first time changed their war cry from "Kyrie Eleison" to their party cries. The Hohenstaufen used the 'Strike for Gibbelins' war cry.
On the death of the Holy Roman Emperor Lothair III (or II) in 1137, Henry the Proud was the Welf heir of the patrimony of his deceased father-in-law, and possessor of the crown jewels. He stood as a candidate for emperor, but the local princes opposed him and elected Conrad III, a Hohenstaufen, in Frankfurt on 2 February 1138. When Conrad gave the Duchy of Saxony to Count Albert the Bear, the Saxons rose in defence of their young prince, and Count Welf of Altorf, the brother of Henry the Proud, began the war.
Exasperated at the heroic defence of Welfs, Conrad III had resolved to destroy Weinsberg and imprison its defenders. However he suspended the final assault after a surrender was negotiated. According to the Latin chronicle Chronica regia...