This paper discusses an aspect ofthe old (probably obsolescent) text-book wisdom conceming the Indo-European ablaut, namely the (once generally accepted) assumption that the o-grade is younger than than the e-grade: the o-grade arose from the e-grade whenever the latter was not accented (under certain additional conditions). The aim of this paper is to show that accented e-grade and unaccented o-grade constitute a possible state of affairs in natura! languages. To this purpose, 1 will make use of Naturalness Theory as currently practised especially in Austrian linguistics (see Dressler 2000), and in my own surroundings at the University ofLjubijana (cf. Orešnik 2001). Naturalness Theory operates with naturalness scales which ascribe greater or smaller naturalness to language units and categories. One of the leading theoreticians in the field ofnatural morphology, Austrian-based Willi Mayerthaler, distinguishes two kinds ofnaturalness, sem- and sym-naturalness (cf. Mayerthaler 1981 etc.). Since 1 will make use of sem-naturalness only in the present paper, and as the latter is very similar to traditional markedness, I will refrain from discussing the difference between sem- and sym-naturalness. 1 will use the bare term naturalness, and set up the follow-ing approximate equations: more natura! = less marked, less natural = more marked. The predicate natural will be abbreviated as 'nat' in scales.