There are two preterit-stem formations in Baltic: *ā-preterit and *ē-preterit. The *ē-preterit includes a category called “long-vowel preterit” that is characterized by the long root vowel. There are at least two hypotheses regarding their origin. First, it has been proposed that these long-vowel preterits may have originated from the imperfect form of Narten presents. Then, it has been suggested that long root vowels were introduced through Stang-Larsson’s rule operating on a variant of the Baltic preterit suffix *-ìyā-, where a vowel was lengthened and received a circumflex tone in a sequence *-V-ìyā- / *-̰-ìyā- > *--iyā (> *--ē). The second hypothesis explains the tone variation of the verbs in the root structure ◦ERK-, ◦EUK-, and ◦ĒK- (e.g., sprsti/sprsti, spréndžia/spreñdžia, spréndė/spreñdė ‘to stretch’ < *(s)prend-). However, this is valid only when the suffix is accented, although the environment for the disyllabic suffix (-ìyā-) must be unaccented according to Sievers-Edgerton’s law. What follows is that the disyllabic suffix originated in the root-accented long-vowel preterits, while the verbs with tone variation probably accepted the disyllabic -ìyā-, so that Stang-Larsson’s rule later operated on them. Interestingly, some of these have a historical relationship with Narten presents, according to a previous study. This article presents the different historical developments of at least two groups of verbs that form the long-vowel preterits through an examination of the accentuation of these verbs.