HJ, here is a lesson. What you have written here is a list, and not a very clear one:
Otto II of Saxony, emperor, born 955
William, Archbishop of Mainz , son of Otto I the Great and unnamed Slav mother.
In 929 Otto married Eadgyth (Edith). Their children were Liudolf of Swabia, duke of Swabia born 930 and Liutgard of Saxony. In 951 he married a second time, Adelaide of Italy, by whom he had Matilda, Abbess of Quedlinburg, born about 954, and Otto II of Saxony, emperor, born 955. Otto had at least one child outside legitimate marriage, William, Archbishop of Mainz, his son by unnamed Slav mother.
- "Saint Adelheid" can be saved for her own entry.
- I've dissolved some space between Otto II and Matilda, and connected them with a conjunction. This is not supposed to be a list with each person on a separate line, but prose.
- I've turned William into a sentence that is connected to the previous material. I also deleted the space between 'Mainz' and the following comma!!!! --MichaelTinkler