The Puster Valley (Italian: Val Pusteria [ˈval pusteˈriːa]; German: Pustertal, Ladin: Val de Puster) is one of the largest longitudinal valleys in the Alps that runs in an east-west direction between Lienz in East Tyrol, Austria, and Mühlbach near Brixen in South Tyrol, Italy. The South Tyrolean municipalities of the Puster Valley constitute the Puster Valley district.
The Synod of Brixen was a church council held on 15 June 1080 in the episcopal city of Brixen. It was convoked by King Henry IV of Germany at the height of the Investiture Controversy to pass judgement on Pope Gregory VII. The synod issued a decree condemning the pope, demanding his abdication and authorizing his deposition if he refused. The synod also elected his successor, Wibert of Ravenna.
Henry IV was at war with a rival claimant to the kingship, Rudolf of Rheinfelden. At the time of the synod, Rudolf had won a recent victory at the battle of Flarchheim on 27 January 1080. In the aftermath of the battle, Henry sent Archbishop Liemar of Bremen and Bishop Rupert of Bamberg to Rome to confer with Gregory at his annual Lenten synod. Rudolf too sent envoys to Rome. On 7 March, the synod chose to recognize Rudolf as the legitimate king. On 13 April, Gregory VII pronounced Henry excommunicated and gave him until 1 August to repent, else "he would die or be deposed". In response Henry convoked the synod of Mainz that met on 31 May. It recommended removing the pope and electing another.