Fries (1981) hypothesises that the textual phenomena of ‘thematic progression’ (TP) (Danesþ 1974) and ‘method of development’ (MOD) provide discourse evidence for the function proposed by Halliday (1967) for Theme, in particular that ‘initial position in the sentence, or sentence-level Theme, means “point of departure of the sentence as message”‘. This paper discusses the theoretical basis for this hypothesis, in particular the relation between TP and MOD, and reviews previous empirical research.