OE had no indefinite article as such; sum A CERTAIN and ān ONE fulfil some of the functions of the PDE indefinite article. In PDE, the definite article is the indeclinable THE. In OE, the definite article seems to have been expressed by the demonstrative se, sēo, þǣt etc., which also means THAT. This determiner agrees with the noun which it modifies in gender, number and case. It is essential to know these forms well, since very often they provide the only sure clue to the grammatical structure of an OE clause.
The paradigm is as follows:
Se etc. can also be used as a pronoun, and often appears with the relative particle þe in relative clauses.
**92. Demonstrative THIS