The goal of the Jewish ketubah is to settle the economic relationship between the groom and bride. The ketubah contains three parts: on the part of the groom, which is the primary objective of the ketubah -the amount of money he is obligated to pay, as well as the addition to the ketubah, should he choose to add to the base amount. On the wife's part, the dowry is detailed. In addition, the dowry also includes the terms of the ketubah, which were meant to ensure the rights of the woman during the marriage and in the case that the marriage is nullified.
Ketubot have not changed much over the centuries. The marriage documents found in Aramaic papyruses from the days of Artaxerxes the King of Persia from the 5th century B.C.E., are very similar to ketubah documents from other eras and even to modern day ketubot. The text in the body of the ketubah, the primary legal content, which is written in Aramaic even today- despite the tendency to translate the text to Hebrew or English, accordingly- shows its incredible consistency throughout 2500 years.
By its very nature, and despite the ancient fixed text, local customs in various communities developed: In North Africa and Yemen husbands were obligated not to force their wives to move from city to city. Occasionally the woman would be obligated to care for the husband's children from a previous marriage as if they were her children. In Syria and Eretz Yisrael the condition forbidding the husband from going on long journeys without first leaving his wife with a conditional divorce in order to protect her from a situation wherein she could become a "chained wife" appears. In addition to these local customs there are a number of widespread conditions found in many ketubot dealing with inheritance arrangements in the case where the couple doesn't have children, arranging a situation wherein the husband wants to take another wife, (in places where that custom was common), as well as paragraphs relating to levirate marriage.