Marriage is variously defined as:
- The legal union of a man and woman as husband and wife.
- The state of being married; wedlock.
- A common-law marriage.
- A union between two persons having the customary but usually not the legal force of marriage: a same-sex marriage.
The last definition is highly controversial, as gay marriage is a hot topic in US politics. Also, interfaith marriage is a sensitive issue in many communities. Many religions do not recognise the concept of marital rape.
- Main Article: Interfaith marriage
Interfaith marriage is a taboo in many societies and religions, particularly for a women marrying outside the faith.
Same sex marriage
- Main Article: Gay marriage
Same sex marriage is the union of two people of the same gender and are typically homosexual in nature. Many religions refuse to conduct same sex marriage ceremonies or to recognize the validity of such marriages. The arguments for and against same sex marriage are largely similar to apologetics relating to homosexuality.
History of Christian marriage in Western Europe
Until the late medieval period, the Christian church did not have any specific marriage rite at all! It is rather hard to argue it is a religious institution when for the majority of Christianity's existence, it has been disinterested in marriage.
- "The early church had no specific rite for marriage. This was left up to the secular authorities of the Roman Empire, since marriage is a legal concern for the legitimacy of heirs. When the Empire became Christian under Constantine, Christian emperors continued the imperial control of marriage, as the Code of Justinian makes clear. When the Empire faltered in the West, church courts took up the role of legal adjudicator of valid marriages. "
Note that church institutions adjudicated marriages but did not perform marriage ceremonies.
High Middle Ages
From 1184 to 1439, the Catholic Church made various decrees that marriage was a sacrament, although possibly not among the most important.
- "Before the eleventh century there was no such thing as a Christian wedding ceremony in the Latin church, and throughout the Middle Ages there was no single church ritual for solemnizing marriage between Christians. "
Marriage was a simply a matter of exchanging vows in front of a witness. Once this was done, the family or church could not undo the marriage.
- "Marriage vows did not have to be exchanged in a church, nor was a priest's presence required. A couple could exchange consent anywhere, anytime. "
Marriages could be annulled if a marriage was not consummated, often by arguing in court that the husband was impotent. The medieval church courts did not allow divorce. In some extreme cases, couples were allowed to separate a mensa et thoro but not remarry.
Late Medieval period
Starting in the sixteenth century, church marriages became more common.  In 1563, the Catholic church passed the Tametsi decree, which declared among other things that no marriage was legitimate unless recognized by the church. Thus, the church declared themselves effectively in charge of families by fiat.
An annulment dispute between Henry VIII of England and the Catholic Church caused the king to declare himself the supreme head of the Church of England in 1534. This enabled him to re-marry and began an era of increased availability of divorces.
Marriage is a Christian institution
Christians claim that marriage is strictly a religious tradition, and that government should not be involved in marriage at all. According to many Christians, marriage is like the relationship between Jesus and the Church. Ephesians 5:21-33 
The idea that marriage originated in the church is a myth.  The early Christian Church considered celibacy to be superior to marriage and had no specific marriage rite. In fact, marriage only became a church ritual around the 11-12th century and only became common towards the sixteenth century. People have been getting "married" for most of mankind's history and has always also involved family, secular affairs, inheritance, jealousy, and questions of paternity.
The claims many theists have that marriage is a religious matter and that government should stay out of it could be correct. However, marriage also has civil implications such as medical decisions, tax filing, custody disputes, inheritance, among many other things. Since we live in a society that uses marriage in these ways, rather than just two people who are "married" in a religious ritual, anyone should be able to get married legally in order to be given the same rights, same-sex or not.
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- ↑ McSheffrey, Shannon (2006). Marriage, sex, and civic culture in late medieval London. University of Pennsylvania Press. p. 21. ISBN 978-0-8122-3938-6. Retrieved April 16, 2012.
- ↑ Anne Laurence, Women In England 1500-1760, Chapter 4, Hachette UK, 2013
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