common wife, which is a unique family structure in the world. Other forms of marriage are also present, like group marriage and monogamous marriage. Polyandry (especially fraternal polyandry) is also common among Buddhists in Bhutan, Ladakh, and other parts of the Indian subcontinent. Celtic traditions Some pre-Christian Celtic pagans were known to practice polygamy, although the Celtic peoples wavered between it, monogamy and polyandry depending on the time period and the area. In some areas this continued even after Christianization began, for instance the Brehon Laws of Gaelic Ireland explicitly allowed for polygamy, especially amongst the noble class. Some modern Celtic pagan religions accept the practice of polygamy to varying degrees, though how widespread the practice is within these religions is unknown. Christianity Although the Old Testament describes numerous examples of polygamy among devotees to God, most Christian groups have rejected the practice of polygamy and have upheld monogamy alone as normative. Nevertheless, some Christians groups in different periods have practiced, or currently do practice, polygamy. Some Christians actively debate whether the New Testament or Christian ethics allows or forbids polygamy. Although the New Testament is largely silent on the subject of polygamy, some point to Jesus's repetition of the earlier scriptures, noting that a man and a wife "shall become one flesh". However, some look to Paul's writings to the Corinthians: "Do you not know that he who is joined to a prostitute becomes one body with her? For, as it is written, 'The two will become one flesh. Supporters of polygamy claim that this verse indicates that the term refers to a physical, rather than a spiritual, union. Some Christian theologians argue that in Matthew 19:3–9 and referring to Genesis 2:24, Jesus explicitly states a man should have only one wife: 1 Timothy 3:2 states: See verse 12 regarding deacons having only one wife. Similar counsel is repeated in the first chapter of the Epistle to Titus. Periodically, Christian reform movements that have sought to rebuild Christian doctrine based on the Bible alone (sola scriptura) have temporarily accepted polygyny as a Biblical practice. For example, during the Protestant Reformation, in a document which was simply referred to as "Der Beichtrat" (or "The Confessional Advice" ), Martin Luther granted the Landgrave Philip of Hesse, who, for many years, had been living "constantly in a state of adultery and fornication", a dispensation to take a second wife. The double marriage