In 977, Queen Emma was accused by her brother-in-law, Duke Charles of Lower Lorraine, of infidelity with Ascelin, Bishop of Laon. The Queen and Bishop were exonerated by the Synod of Sainte-Macre, led by Adalberon, Archbishop of Rheims, and Charles was forced to flee Western Francia. Emma, to ensure her son’s succession, then persuaded Lothair to crown him as associated king; Lothair did so, but refused to let him have any real power.
Emma’s marriage to Lothair was marked by hostilities between her husband and her half-brother, Otto II, each invading the other’s territories, and attempting to destabilise each other, often through the intermediary of Lothair’s brother, Charles (who as Duke of Lower Lorraine was a vassal of the Emperor). The final years of their marriage, however, from 980 onwards, saw peace between Lothair and his in-laws; when Otto II died, he was even advanced as guardian of the young King.
Lothair died on 2 March 986, and their young son Louis became king. However, he promptly drove Emma and Bishop Ascelin of Laon from the court, accusing them of having poisoned Lothair. Louis then died on 22 May 987, without an heir. In the following months, her brother-in-law Charles seized the royal capital of Laon and declared himself king; Hugh Capet, Duke of the Franks, was elected and crowned king by the agencies of Adalberon on 3 July 987. In the resulting conflicts, Ascelin betrayed Charles to Hugh Capet, as a result of which the last Carolingian was imprisoned in Orleans.
Emma's doings following the death of her son are unclear; she is believed to have died in a Burgundian convent or married Duke Boleslaus II (being identical to Emma of Mělník) and possibly had a son called Oldřich.