||This thesis attempts to find explanations for the longus in brevī (LIB) syllables, heavy syllables in light positions, encountered in the Ṛgveda. After an introduction to the Ṛgvedic text and its metre, the data consisting of LIB syllables in the second syllable of the break of trimeter verses with late caesura are discussed. The research points out that there are no phonological environments that can explain the LIB syllables. Furthermore, it shows that there is no correlation between age and percentage of LIB syllables. Next, the findings of the research are presented. A portion of the data is explained by Bhārgavī verses, a metrical variation marked by a jagatī cadence although containing only 11 syllables, in hymn 77 and 78 of Book 10. The research proceeds to show that verses in other hymns containing a similar cadence cannot be seen as Bhārgavī verses because of a different pattern of the break. A number of them are solved by adding a pause after the caesura. At last, the thesis reveals two textual corrections that explain a number of verses. Two verses contain verbs with the -āyá-suffix in the second syllable of the break. These forms have been attracted into the larger category of -áya-causatives at the time of composing and have later been restored in their original forms, which did not accord with the metre anymore. The last textual correction is in the -e- of the word jyeṣṭha-, that is etymologically made up of two syllables. Some occurrences can be counted as disyllabic, others as monosyllabic. This is explained as either a handy poetic tool, or a difference between the archaic family books and the more modern books.