* November – At the death of his father, Welf I, Duke of Bavaria, Welf II, Duke of Bavaria becomes duke of Bavaria.

* November 6 – Welf I, duke of Bavaria.

But the Welf duke of Saxony, Henry the Lion, would not be appeased.

In order to secure Welf support for his election, Lothair married Gertrude to Henry the Proud, the duke of Bavaria, on May 29, 1127.

He inherited the property of his maternal uncle, Welf, Duke of Carinthia, became duke of Bavaria in 1070, and is the ancestor of the elder branch, the House of Welf.

Upon the deposition of the Welf duke Henry the Lion in 1180, the ducal title fell to the House of Ascania, in 1296 the remaining lands were divided into the duchies of Saxe-Wittenberg and Saxe-Lauenburg.

In 1070, Welf IV became duke of Bavaria.

Henry the Black, duke of Bavaria from 1120 – 1126, was the first of the three dukes of the Welf dynasty carrying the same name.

In 1313, he wed Adelaide of Brunswick ( 1285 – 1320 ), daughter of the Welf duke Henry I of Brunswick-Grubenhagen.

Margaret was the only surviving daughter of Henry of Gorizia-Tyrol, then Duke of Carinthia and Count of Tyrol, with his second wife Adelaide, daughter of the Welf duke Henry I of Brunswick-Lüneburg.

In September 1198 Frederick's younger half-brother Ottokar I made use of the rivalry among Otto IV from the House of Welf and the Hohenstaufen duke Philip of Swabia, youngest son of Emperor Frederick Barbarossa, who both had been elected King of the Romans.

By the peace of Gerstungen on 2 February 1074 Bavaria was formally restored to him, which however met strong opposition with the result that Otto's former son-in-law Welf I de facto remained duke.

After the Welf duke Henry the Lion was placed under Imperial ban in 1180, Eastphalia was increasingly subdivided into smaller states, foremost the Welf Duchy of Brunswick-Lüneburg and the counties of Anhalt, Wernigerode and Blankenburg as well as the Imperial city of Goslar, but also the ecclesiastical territories of the Archbishopric of Magdeburg, the prince-bishoprics of Hildesheim and Halberstadt and Quedlinburg Abbey.

He was succeeded as duke of Bavaria by his son Welf.

Welf II ( 1072 – 24 September 1120, Kaufering ), or Welfhard, called Welf the Fat, was duke of Bavaria from 1101 until his death.

Since Matilda had secretly transferred her property to the Church before her marriage, Welf left her in 1095 and, together with his father, changed sides to King Henry IV, possibly in exchange for a promise of succeeding his father as duke of Bavaria.

After his father's death in 1101 Welf indeed inherited the office of duke of Bavaria.

Henry IX ( 1075 – 13 December 1126 ), called the Black, a member of the House of Welf, was duke of Bavaria from 1120 to 1126.

When he died in 1138, the princes again aimed at checking royal power ; accordingly they did not elect Lothair's favoured heir, his son-in-law Henry the Proud of the Welf family, but Conrad III of the Hohenstaufen family, close relatives of the Salians, leading to over a century of strife between the two houses.

He had vanquished one notable opponent, his Welf cousin, Duke Henry the Lion of Saxony and Bavaria in 1180, but his hopes of restoring the power and prestige of the monarchy seemed unlikely to be met by the end of his life.

In 1198, two rival kings were chosen: the Hohenstaufen Philip of Swabia and the son of the deprived Duke Henry the Lion, the Welf Otto IV.

It is the business of the pope to look after the interests of the Roman empire, since the empire derives its origin and its final authority from the papacy ; its origin, because it was originally transferred from Greece by and for the sake of the papacy ... its final authority, because the emperor is raised to his position by the pope who blesses him, crowns him and invests him with the empire .... Therefore, since three persons have lately been elected king by different parties, namely the youth son of Henry VI, Philip Hohenstaufen, brother of Henry VI, and Otto Brunswick, of the Welf family, so also three things must be taken into account in regard to each one, namely: the legality, the suitability and the expediency of his election ...... Far be it from us that we should defer to man rather than to God, or that we should fear the countenance of the powerful .... On the foregoing grounds, then, we decide that the youth should not at present be given the empire ; we utterly reject Philip for his manifest unfitness and we order his usurpation to be resisted by all .... since Otto is not only himself devoted to the church, but comes from devout ancestors on both sides ..... therefore we decree that he ought to be accepted and supported as king, and ought to be given the crown of empire, after the rights of the Roman church have been secured.

After the death of Emperor Henry VI, who had recently also conquered the Kingdom of Sicily, the succession became disputed: as Henry's son Frederick was still a small child, the partisans of the Staufen dynasty elected Henry ’ s brother, Philip, Duke of Swabia, king in March 1198, whereas the princes opposed to the Staufen dynasty elected Otto, Duke of Brunswick, of the House of Welf.

Most importantly, he managed to secure the Welf inheritance in Saxony for his nephew, Henry the Lion's son Otto of Poitou, who was elected Otto IV of Germany in 1198.

His daughter Wulfhilde married Henry IX, Duke of Bavaria, a member of the House of Welf ; his daughter Eilika married Otto, Count of Ballenstedt, a member of the House of Ascania.

His mother was Judith, daughter of Henry IX, Duke of Bavaria, from the rival House of Welf, and Frederick therefore descended from Germany's two leading families, making him an acceptable choice for the Empire's prince-electors.

After Henry's death ( October 1139 ), the war was continued by his son Henry the Lion, supported by the Saxons, and by his brother Welf VI.

In 1150, Conrad and Henry Berengar defeated Welf VI and his son Welf VII at the Battle of Flochberg.

Henry the Lion (; 1129 – 6 August 1195 ) was a member of the Welf dynasty and Duke of Saxony, as Henry III, from 1142, and Duke of Bavaria, as Henry XII, from 1156, which duchies he held until 1180.

He was the son of Henry the Black, Duke of Bavaria, and Wulfhilde, daughter of Magnus Billung, Duke of Saxony, and thus a member of the Welf family, and, what was quite important, senior heir of the Billung family.

The Welf Henry X the Proud, Duke of Bavaria since 1126, becomes Duke of Saxony, as Henry II.

In 1142 King Conrad III of Germany granted the ducal title to the Welf scion Henry the Lion ( as Duke Henry III ).

In the course of the dispute between the Welfen and Staufen dynasties in the Holy Roman Empire, the duchy of Bavaria had been taken away from the Welf Henry the Proud by the emperor and given to the Babenberg dynasty.

At the beginning of the 13th century, Philip of Swabia, a Hohenstaufen, and his son-in-law Otto of Brunswick, a Welf, were rivals for the imperial throne.

In 1195, the Palatinate passed to the House of Welf through the marriage of Agnes, heir to the Staufen count.

His duchy was given to Lothair of Supplinburg and his lands were split between his daughters by Sophia ( married 1071 ), the daughter of Béla I of Hungary, going thus to the house of Welf, via Wulfhilde ( 1075 – 1126 ), who married Duke Henry IX of Bavaria and to the house of Ascania via Eilika ( 1080 – 16 January 1142 ), who married Count Otto of Ballenstedt.

However, the kingship subsequently ended up in the hands of the Staufens, destroying Lothair's hopes for a powerful Welf hereditary monarchy.

* July – Otto of Brunswick is crowned King of Germany by the House of Welf.

Carloman () ( 830 – 29 September 880 ) was the eldest son of Louis the German, king of East Francia ( Germany ), and Hemma, daughter of the count Welf.

The title " Duke of Brunswick and Lüneburg " () was held, from 1235, by various members of the Welf family who ruled several small territories in northwest Germany.

The title " Duke of Brunswick and Lüneburg " () was held, from 1235 on, by various members of the Welf family who ruled several small territories in northwest Germany.

Nicknamed the Royal City ( reflecting the House of Hanover, known in its native Germany as the House of Welf ), Guelph's street railway operated from 1895 until 1939 along five routes.

Although the Marquis of Este, guided by his cousin Matilda, continued firm in the Pope's interests, his son Welf, who had succeeded to the Bavarian states, and whose views were more immediately directed to Germany, supported the emperor.