Mycenaean o- is accusative; jo- is nominative

This paper argues that the distinction between introductory o- and jo- in Mycenaean correlates with text structure. In a tablet introduced by o-, the level of structure immediately dependent on the main heading gives information about the object of the verb in the heading. In a text introduced by jo-, the same level of structure gives information about the subject of the verb. It is argued that o- represents the accusative singular neuter of the relative pronoun while jo- represents its nominative plural masculine. Possible explanations for the different orthographies are suggested.