Short answers, pulled from the story.
In Old English, the word wife meant simply woman and referred to any adult female regardless of her relationship status. This general descriptor evolved into a specific legal and social role as marriage became institutionalized in Germanic languages.
The Married Women's Property Act of 1882 established that a wife's property rights were virtually non-existent in the English-speaking world before this date. This legislation ended the legal erasure where a feme covert could own little property in her own name and was unable to sue or be sued independently.
In ancient Rome, the legal age for a bride to marry was set at 12 years old. This standard was later adopted by Roman Catholic canon law and persisted in various forms for centuries, with noble women known to marry as young as 12 years of age.
Switzerland, Greece, Spain, and France were among the last European countries to establish full gender equality in marriage during the 1980s. A referendum in Switzerland guaranteed women legal equality with men within marriage in 1985, with reforms coming into force in January 1988.
The economic independence theory suggests that if one side of the couple provides more than 60% of the total income, a dependence effect occurs. This alters the power dynamics within the relationship and has historically been the primary mechanism for securing a woman's status.