The study of the ages women marry and the age gap between husband and wife is well accepted by social-economic historians and demographers as it is highly associated with the growth of a population. There is however another reason for studying marriage patterns, that of female agency. Young girls who marry men many years their senior are likely left with very little say as to the terms of the union and later decisions made within the household. This is a hypothesis that has been explored by a number of authors recently as marriage patterns data is available on a large scale over a long time period. But how good a measure are ages at marriage of women and spousal age gaps. Rather than explore the mechanisms underlying this relationship this paper seeks to test marriage patterns as a measure of female empowerment by comparing a global set of marriage patterns data against three measures currently in use in the international development community, the Gender –related Development Index, the Global Gender Gap Index and the Gender Inequality Index. We use a new index of marriage ages (the Girlpower-Index) constructed by subtracting spousal age gap from marriage age and find that female SMAM and the Girlpower-Index both correlate strongly with the modern gender empowerment indices. This lends support to the use of marriage patterns as a historical measure of gender empowerment.