Frederick I, Holy Roman Emperor in the context of "Mainz-Kostheim"

An Imperial Estate (Latin: Status Imperii; German: Reichsstand, plural: Reichsstände) was an entity or an individual of the Holy Roman Empire with representation and the right to vote in the Imperial Diet (Reichstag). Rulers of these Estates were able to exercise significant rights and privileges and were "immediate", meaning the only authority above them was that of the Holy Roman Emperor. They were thus able to rule their territories with a considerable degree of autonomy.

The system of imperial states replaced the more regular division of Germany into stem duchies in the early medieval period. The old Carolingian stem duchies were retained as the major divisions of Germany under the Salian dynasty, but they became increasingly obsolete during the early high medieval period under the Hohenstaufen, and they were finally abolished in 1180 by Frederick Barbarossa in favour of more numerous territorial divisions. From 1489, the Imperial Estates represented in the Diet were divided into three chambers, the college of prince-electors (Kurfürstenkollegium/den Kurfürstenrat), the college of imperial princes (Reichsfürstenrat) and the college of imperial cities. Counts and nobles were not directly represented in the Diet in spite of their immediate status, but were grouped into "benches" (Grafenbänke) with a single vote each.Imperial Knights and imperial villages had immediate status but were not represented in the Diet.

The Hohenstaufen dynasty (/ˈhoʊənʃtaʊfən/, US also /-staʊ-/, German: [ˌhoːənˈʃtaʊfn̩]), also known as the Staufer, was a noble family of German origin that rose to rule the Duchy of Swabia from 1079, and to royal rule in the Holy Roman Empire during the Middle Ages from 1138 until 1254. The dynasty's most prominent rulers – Frederick I (1155), Henry VI (1191) and Frederick II (1220) – ascended the imperial throne and also reigned over Italy and Burgundy. The non-contemporary name of 'Hohenstaufen' is derived from the family's Hohenstaufen Castle on Hohenstaufen mountain at the northern fringes of the Swabian Jura, near the town of Göppingen. Under Hohenstaufen rule, the Holy Roman Empire reached its greatest territorial extent from 1155 to 1268.

The Duchy of Bavaria (German: Herzogtum Bayern) was a frontier region in the southeastern part of the Merovingian kingdom from the sixth through the eighth century. It was settled by Bavarian tribes and ruled by dukes (duces) under Frankish overlordship. A new duchy was created from this area during the decline of the Carolingian Empire in the late ninth century. It became one of the stem duchies of the East Frankish realm, which evolved as the Kingdom of Germany and the Holy Roman Empire.

During internal struggles in the Ottonian dynasty, the Bavarian territory was considerably diminished by the separation of the newly established Duchy of Carinthia in 976. Between 1070 and 1180, the Holy Roman Emperors were again strongly opposed by Bavaria, especially by the ducal House of Welf. In the final conflict between the Welf and Hohenstaufen dynasties, Duke Henry the Lion was banned and deprived of his Bavarian and Saxon fiefs by Emperor Frederick Barbarossa. Frederick passed Bavaria over to the House of Wittelsbach, which held it until 1918. The Bavarian dukes were raised to prince-electors during the Thirty Years' War in 1623, and to kings by Napoleon in 1806. The duchy chaired the bench of the secular princes to the Reichstag of the Empire.

A stem duchy (German: Stammesherzogtum, from Stamm, meaning "tribe", in reference to the Franks, Saxons, Bavarians and Swabians) was a constituent duchy of the Kingdom of Germany at the time of the extinction of the Carolingian dynasty (death of Louis the Child in 911) and through the transitional period leading to the formation of the Ottonian dynasty. The Carolingians had dissolved the original tribal duchies of the Empire in the 8th century. As the Carolingian Empire declined, the old tribal areas assumed new identities. The five stem duchies (sometimes also called "younger stem duchies" in contrast to the pre-Carolingian tribal duchies) wereBavaria, Franconia, Lotharingia (Lorraine), Saxony and Swabia (Alemannia). The Salian emperors (reigned 1027–1125) retained the stem duchies as the major divisions of Germany, but the stem duchies became increasingly obsolete during the early high-medieval period under the Hohenstaufen, and Frederick Barbarossa finally abolished them in 1180 in favour of more numerous territorial duchies.

The term Stammesherzogtum as used in German historiography dates to the mid-19th century, and from the beginning was closely related to the question of national unification. The term's applicability, and the nature of the stem duchies in medieval Germany, consequently have a long history of controversy.The overly literal or etymologizing English translation "stem duchy" was coined in the early 20th century. While later authors tend to clarify the term by using the alternative translation "tribal", use of the term "stem duchies" has become conventional.

Pope Lucius III (c. 1100 – 25 November 1185), born Ubaldo Allucingoli, reigned as head of the Catholic Church and ruler of the Papal States from 1 September 1181 to his death in 1185. Born to an aristocratic family in Lucca, prior to being elected pope, he had a long career as a papal diplomat. His papacy was marked by conflicts with Holy Roman Emperor Frederick I, his exile from Rome, and the initial preparations for the Third Crusade.

Born in Lucca, Ubaldo Allucingoli rose to prominence within the Catholic Church, eventually becoming Pope Lucius III. He was appointed cardinal by Pope Innocent II and served as papal legate in France, Sicily, and other regions. He was involved in negotiating the Treaty of Venice in 1177, and was elected pope in 1181.

Ad abolendam (lit. 'On abolition / Towards abolishing'; full title in Latin: Ad abolendam diversam haeresium pravitatem, lit. 'To abolish diverse malignant heresies') was a decretal and bull of Pope Lucius III, written at Verona and issued 4 November 1184. It was issued after the Council of Verona settled some jurisdictional differences between the Papacy and Frederick I, Holy Roman Emperor. The document prescribes measures to uproot heresy and sparked the efforts which culminated in the Albigensian Crusade and the Inquisitions. Its chief aim was the complete abolition of Christian heresy.