Short answers, pulled from the story.
Saint Boniface founded the diocese of Salzburg in 739 within the German stem duchy of Bavaria. The capital city grew from a former Roman settlement into an ecclesiastical principality over centuries.
Archbishop Eberhard II of Regensberg received princely status for the Empire in 1213. He established three new sees including Chiemsee, Seckau, and Lavant during his tenure.
Five historic districts divided the land into Flachgau, Tennengau, Pinzgau, Pongau, and Lungau. Flachgau contained the capital city while Tennengau surrounded Hallein near the Northern Limestone Alps.
During the reign of Leopold Anthony of Firmian remaining Protestants were expelled in 1731 after recanting beliefs became impossible. Over twenty thousand Salzburg Protestants were forced to leave their homes and most accepted an offer of land by King Frederick William I of Prussia following their expulsion.
Hieronymus von Colloredo served as the last Prince-Archbishop exercising secular authority until 1803. His reforms of church and education systems alienated him from the people of Salzburg and he reigned from 1772 to 1812 during a period of significant cultural development.
Salzburg was secularised as the Electorate of Salzburg in 1803 for Ferdinand III of Tuscany who had lost his throne and received this territory as compensation for his losses. The state ceased to exist as a political entity after losing its independence in 1803 and the archdiocese was reestablished as the Roman Catholic Archdiocese of Salzburg in 1818 without any temporal power.