icelandic pro appears to be case-marked. rules of case agreement in icelandic require that floated quantifiers agree in case (as well as in number and gender) with the dp they quantify. as illustrated in (18) and (19), this agreement requirement holds of pro. in (18), the quantifier báðir 'both' appears in the nominative masculine plural form. in (19), the quantifier báðum 'both' appears in the dative plural form. the occurrence of such forms indicates that the quantifiers are agreeing with their antecedent, namely pro. this leads to the conclusion that pro must be case-marked, and this is possible only if pro is in spec-tp.