significant economic implications for the parties involved: the first child born to the brother's widow would be deemed the heir of the deceased brother, and able to claim the deceased brother's share of inheritance. If the deceased brother was the firstborn son, his inheritance was a double share. However, if the deceased brother were childless, the living brother would be entitled to inherit an increased share; or if he is the oldest surviving son he would be entitled to a double share of the increased share. Levirate-type marriages other than yibbum A detailed account of a levirate-type marriage in the Hebrew Bible is the unusual union of Judah and his daughter-in-law Tamar found in . The case is not strictly a case of yibbum as Judah was Tamar's father-in-law, and also the case pre-dates the biblical obligation. It may be a reflection of contemporaneous Middle East practices. Tamar's earlier marriage to Onan, however, did conform with the specific circumstances describing the requirements of yibbum outlined in Deuteronomy, as Onan was the brother of Tamar's deceased husband Er. Another example of an analogous arrangement to yibbum is recounted in the Book of Ruth. After the death of her husband, Ruth is noticed and welcomed by her husband's kinsman, Boaz. After Ruth is rejected by an anonymous Ploni Almoni, Boaz marries her. In this case as well, the kin in question would not have been subject to the biblical levirate marriage obligation, as neither Ploni Almoni nor Boaz were brothers of Ruth's late husband. Laws of yibbum and halizah Halakha (Jewish law) has a rich tradition around yibbum. These laws were first recorded in the Mishna and Talmud in Yevamot, and were later codified by Maimonides in the Mishneh Torah. The subject is considered one of the most intricate in Jewish law, partly because of the complication that arise from multiple brothers and multiple wives. Yibbum is an exception to the biblical prohibition for a man to have sexual relations with "his brother's wife" found for example in and . (See Incest in the Bible.) When yibbum applies The obligation for yibbum is found at , which requires that when a married man dies without having any children, male or female, from any relationship (including pre-marital and extra-marital), his widow and his brother must perform either yibbum or halizah. For the laws of yibbum only brothers that share a common father are