They're both genitive, (German) [des] aberils and (Latin) aprilis.
Anno [dominii] 1372 des sibten tages des aberils ··· = AD 1372 of the 7th day of april
VII tag aprilis = 7(th) day of april
Glossary seems to list the nominative case yup
There's also an entry for augst on p361
Anno [dominii] 1372 des sibten tages des aberils ··· = AD 1372 of the 7th day of april
VII tag aprilis = 7(th) day of april
Glossary seems to list the nominative case yup
There's also an entry for augst on p361


