This dissertation investigates the distribution of the pronominal clitics and the modal particle an in fifth-century Greek (more specifically in Herodotus, the tragedians, and Aristophanes), which is typically assumed to be governed by Wackernagel's Law. It argues for a prosody-dominant model of clitic distribution, according to which the position of a clitic is conditioned primarily by prosodic domain, and only secondarily by syntactic domain: clitics typically select for a host at the left edge of an intonational phrase. From here I then pursue the deeper question of what factors are responsible for the mapping of a constituent (or sub-constituent) onto an intonational phrase. I examine preposed phrases, participial phrases, and infinitival clauses, to present a dossier of the pragmatic and semantic meanings that induce intonational-phrase coding, and in turn shape clitic distribution.