Editing Otto II, Holy Roman Emperor (section)

===War against France===
{{further|Franco-German war of 978–980}}
Before Henry II's civil war in southern Germany erupted, Otto II was faced with disputes in western Germany. The brothers [[Reginar IV, Count of Mons]], and [[Lambert I, Count of Louvain]], demanded that the Emperor restore their confiscated inheritance in the [[Duchy of Lorraine]].{{sfn|Reuter|2000|p=254}} Years earlier in 958, Otto the Great banished their father [[Reginar III, Count of Hainaut]], to [[Bohemia]] after he attempted a failed revolt. In 973, Otto II granted their request. With both Otto the Great and Count Reginar III dead, it appears Otto II desired a fresh start with the two sons. Lambert I and Reginar IV returned to Lorraine in 973 to reclaim their land by force. After an initial failure, the brothers attempted again in 976, this time with the support of King [[Lothar of France]]. To help calm the situation in the west, Otto II appointed [[Charles, Duke of Lower Lorraine|Charles]], his cousin and brother of Lothar, as [[Duke of Lower Lorraine]]. The same year, Otto II appointed [[Egbert (Archbishop of Trier)|Egbert]] as his Imperial Chancellor.

Otto II's support of Charles, however, infuriated the French king, who claimed the Duchy as his own territory.{{sfn|Reuter|2000|p=254}} Charles and Lothair were also feuding, with Charles being exiled from France over an infidelity allegation he had made against Lothair's wife. Charles fled to Otto II's court and paid homage to Otto II. In return, Otto II appointed Charles as Duke and promised to support his claim to the French throne. Soon after Otto II crushed Henry II's revolt in the south, the Emperor and his wife [[Theophanu]] returned to the old capital of [[Aachen]] in [[Lorraine (province)|Lorraine]]. With the Imperial family near the French border, Lothair invaded Lorraine and marched on Aachen.<ref name="Comyn, pg. 118"/> With the French army in sight, Otto II and Theophanu fled to [[Cologne]] and then to the [[Duchy of Saxony]]. Upon hearing of the French invasion, Otto II's mother [[Adelaide of Italy]], who was Lothair's mother-in-law, sided with Lothair over her own son and moved to the court of her brother [[Conrad of Burgundy|King Conrad]] of [[Burgundy]].<ref name="Comyn, pg. 117" /> After occupying Aachen for five days, Lothair returned to France after symbolically disgracing the city.

Otto II convened the Imperial Diet in mid-July at [[Dortmund]]. There, Otto II declared war against France and prepared his army to march west. In September 978, Otto II retaliated against Lothair by invading France with the aid of Charles.{{citation needed|date=August 2018}} He met with little resistance on French territory,<ref name=EB1911/> devastating the land around [[Rheims]], [[Soissons]], and [[Laon]]. Otto II then had Charles crowned as King of the Franks by [[Theodoric I, Bishop of Metz]]. Lothair then fled to the French capital of Paris and was there besieged by Otto II and Charles. Sickness among his troops brought on by winter and a French relief army under [[Hugh Capet]] forced Otto II and Charles to lift the siege on November 30, and to return to Germany. On the journey back to Germany, Otto's [[rearguard]] was attacked and destroyed by French forces, with their supplies being captured.<ref name="Comyn, pg. 118"/> Despite neither side obtaining a clear victory, Otto II felt his honor was sufficiently restored and opened peace negotiations with the French King. Peace was finally concluded between Otto II and Lothair in 980: in return for renouncing his claims on Lorraine, Otto II would recognize Lothair's son [[Louis V of France|Louis V]] as the rightful heir to the French throne.<ref name="Comyn, pg. 118">Comyn, p. 118</ref>

With peace concluded, Otto II returned to Aachen to celebrate [[Pentecost]], and then moved towards [[Nijmegen]]. During the journey, in late June or early July 980, the Empress Theophanu gave birth to the Imperial couple's only son: [[Otto III, Holy Roman Emperor|Otto III]].