Keywords: historical morphology, language change, declension, analogy.

The Old Icelandic possessive pronouns okkarr, ykkarr and yð(v)arr were declined according to gender, number and case, i.e. 24 forms for each pronoun, of which 13 were phonologically different.

Instead of these inflected (and agreeing) possessive pronouns Modern Icelandic uses the genitive of the corresponding personal pronouns við (1p.), þið (2p.) and þér (2p. polite form), viz. okkar, ykkar and yðar. This is one of the major differences between Old and Modern Icelandic. Several facts about this change are well known. But the present study is an attempt to provide a more detailed and comprehensive survey. A number of written sources make this possible (see tables 5–19).

The main change took place in the period 1500–1650 (see table 20). At the outset the change was slow, then it became fairly rapid, but in the end it slowed down. Some forms disappeared early, e.g. nom.fem.sg. and nom.acc.neut.pl., but others survived for a long time, especially nom.acc.neut.sg. (okkart, ykkart, yðvart).

It follows that the change took place in several stages (see (5) in section 3.3). Attempts are made to define and explain those stages. The main problem is of course why this change took place at all. Some explanations, old and new, are discussed, including a sound change leading to syncretism, analogical changes, etc.