Marriage is the most important, sacred and essential Sanskaar in Hinduism. By this Sanskaar people enter the Grihasth Aashram which is the most important Aashram in a human being's life. All other three Aashram depend on this Aashram only. Devtaa get their food from this Aashram only.

According to Manu Smriti marriage ceremony is a Yagya (a serious act to please God). According to Shatapath Braahman, a man and a woman are complete only when they have found each other. During the Vaidik age, the age of marriage for a man was around 24 years, and for a woman it was somewhat a little less. During these years they had the opportunity to find each other, if yes, it was called Gaandharv Vivaah. (see below "Types of Vivaah). In royal families, there was a practice of Swayamvar, where the men desirous to marry the girl will gather on an appointed date; and the girl had the right to choose her husband. During the Vaidik age, the widow was not only permitted to marry but was encouraged - see 10-18-8 of Rig Ved and 9-5-27 of Atharv Ved.

With the invasions of Muslims, the things changed and the boys and girls were not allowed to meet each other and the marriages were settled by parents. The schooling of girls also vanished after the age of 10 or so. This situation lasted until the mid 20th century and the criteria for both boy and girl changed. Wealth and caste became a big consideration. Engagement ceremony became an important part of the sacrament. A month to 2 years elapsed between the date of engagement and actual marriage. Until 1955, divorce was not allowed in the Hindoo society. The woman became dependent on her husband and in many instances had to suffer humiliation and inhuman treatment from the husband.

Many Grihya Sootra were written during this period in which marriage was described in detail, but most of them were very similar. Hindoo marriage ceremony followed these Sootra written during 600-200 BC consisting of - (1) Varamaalaa - placing a garland around the neck of each other; (2) invocation by the Priest; (3) worship by the parents of the girl; (4) Kanyaa Daan - giving away of the girl by girl's parents; (5) Paanigrahan - boy and the girl accepting each other by holding the hand of each other; (6) Granthi Bandhan - tying the knot between their clothes; (7) Parinaya - circumambulation of sacred fire several times, minimum 3 times and maximum 7 times; (8) marriage vows; (9) Saptpadee - seven prayers by the new family; (10) Saubhaagyinee - putting vermillion in the hair parting of the girl by the boy; (11) placing Mangalsootra around the neck of the girl to wish her all the fortune; and lastly (12) Mangalaacharan - benediction by all present.

Rig Ved and Atharv Ved are the major sources of the Mantra used for marriage ceremony. When everything else is found satisfactory the horoscopes are compared and many possible relationships are abandoned if they do not match. Even these marriages take place on certain days of the year.
[Aangiras, p 340-342]

Types of Vivaah
(Bhavishya Puraan, 23) There are eight types of marriages. Manu Smriti, 6.21 also lists the same. :--

(1) Braahm Vivaah -  to invite a noble man himself, to adorn him with ornaments and worship him, and to offer one's daughter to him is called Braahm Vivaah. In this there is no system of dowry. One of the most important ritual of this marriage is Kanyaa Daan (where the father gifts his daughter to the groom.) Among the eight types of the marriages, this is highest type of marriage in the Dharm Shaastra.

(2) Daiv Vivaah - When people are doing Yagya together, to offer one's daughter to such a Braahman is called Daiv Vivaah. In this kind of a marriage the girl's family looks for a suitable groom for their daughter and if nobody turns up, they go looking for a groom in such places where a sacrifice is being conducted. According to the religious texts Daiv marriage is inferior to Braahm marriage. It is considered degrading for the woman to look for groom by herself or by her family.

(3) Aarsh Vivaah - This type of marriage is performed among sages. Taking two cows from the groom for the purpose of Dharm and marrying one's daughter to him is called Aarsh Vivaah. Marriages of this type are said to have happened when the parents of the bride couldn't afford the expense of their daughter's marriage at the right time. The girl is married to an old sage without her choice. This is not considered as a noble marriage as it involves monetary or business transaction.

(4) Praajaapatya Vivaah - This kind of marriage is almost similar to the Braahm marriage. There are only two major differences between them, one is that there is no monetary transaction involved in it, and Kanyaa Daan is not a part of Praajaapatya marriage. In this marriage the bride's father goes in search for a groom for his daughter. "You follow Grihasth Dharm living together", when after saying such words, the father of the bride offers his daughter after worshipping the groom, that is called Praajaapatya Vivaah.

(5) Asur Vivaah - When a marriage is performed freely after giving enough wealth to bride and her father, that is called Asur or Aasuree Vivaah. So this is a kind of a business.

(6) Gaandharv Vivaah - Whatever Vivaah is performed with the free will of bride and groom, that is called Gaandharv Vivaah. It is like the modern day love marriage. Here the bride and the bridegroom marry secretly without the knowledge of their parents. It is not regarded to be a right kind of marriage as it is against the will of the parents so it is inferior kind of marriage. Dushyant and Shakuntalaa's marriage is the best example for it.

(7) Raakshas Vivaah - The Raakshas marriage is done, when the groom fights battle with the bride's family, defeats them and then carries the bride away and then persuades her to marry him. This is not at all considered as the right kind of marriage as it includes force. It may involve crying woman, beating her cruelly for marriage etc activities. When Raavan brought many women to his kingdom and married them, this is the example of Raakshas Vivaah.

(8) Paishaach Vivaah - Paishaach marriage is the last kind of marriage. It is considered as the most inferior type of marriage. In this the girl is married against her wishes. It may involve abducting a sleeping, drunk, or mad woman for marriage. This kind of marriage is prohibited.

Other Types of Marriages
Agni Puraan mentions 4 types of Vivaah

Because of Yagyopaveet Sanskaar, Braahman, Kshatriya and Vaishya are called Dwij. If a child is born to a couple married according to Anulom Vivaah (higher Varn boy and lower Varn girl), that child belongs to mother's caste. If a child is born to a couple married according to Pratilom Vivaah (lower Varn boy and higher Varn girl), he is -

Shoodra boy + Braahman girl = Chaandaal child;
Kshatriya boy + Braahman girl = Soot child;
Vaishya boy + Braahman boy = Vaidehak child
Shoodra boy + Kshatriya girl = Pukkas (Vilomaj child)
Vaishya boy + Kshatriya girl = Maagadh (Vilomaj child)
Shoodra boy + Kshatriya girl = A-Yogav (Vilomaj child)

There are many types of children who are born to a Vaishya girl married a Vilomaj boy. They should marry among themselves

(1) Anulom Vivaah - When a higher Varn man marries a lower Varn woman, it is called Anulom Vivaah. There are many examples of Anulom Vivaah in our scriptures -
(1) Kardam Rishi who married King Priyavrat's daughter Devahooti;
(2) Bhrigu's son Rishi Chyavan who married King Sharyaati's daughter Sukanyaa;
(3) Saubhari Rishi married 50 daughters of King Maandhaataa;
(4) Agastya Rishi married to Vidarbh King's daughter Lopaamudraa
(5) Richeek Muni married Kushik family's Satyavatee by giving 1,000 special horses
(6) Rishi Rishyashring who married King Rompaad's daughter Shaantaa.

This type of Vivaah also came to cease by MBH times. The last such Vivaah seems to be between the Braahman King Agnimitra and Kshatriya daughter Maalvikaa. (Kaalidaas has written "Maalvikaagnimitra" based on their love story)

(2) Pratilom Vivaah - When a lower Varn boy marries a higher Varn girl, it is called Pratilom Vivaah. Typical examples of Pratilom Vivaah are of King Yayaati who married Shukraachaarya's daughter Devayaanee; King Asang married to Angiras Muni's daughter Shashavatee. But in due course of time this type of Vivaah stopped completely, but Anulom Vivaah continued for some time more. It is not uncommon even today. (see below under "Anulom Vivaah")

(3) Putrikaa Dharm Vivaah - In this type of Vivaah, the parents marry their daughter with the condition that her first son will be their son. It normally happens when the parents don't have a son, but it can happen otherwise also. Manu married his daughter Aakooti to Ruchi Prajaapati according to this Dharm and thus had her son as his own son, although he had already had two sons of his own. Arjun married to Chitraangadaa in the same way.

Steps to Follow the Ceremony
(1) Vaag Daan, Tilak or Shagun (Engagement) - Commitment by the bride's parents to complete the marriage on a future date with the acceptance of the parents of bridegroom.

Vivaah in Sanskrit means "carrying out special social responsibility of accomplishment of the four Purushaarth of life such as Dharm, Arth, Kaam and Moksh with the help of one's spouse, living a life of a "house holder". Manu Smriti also describes the qualification of an eligible groom and eligible bride. Whatever be the form of Dara-Parigraha; eligibility of the groom or bride is foremost pre-condition. If this pre-condition is found lacking- the chances of marital disharmony are much more.

Number of Marriages in Atharv Ved
See also   Hymns on Marriage in Atharv Ved

Atharv Ved, 6th volume, 14th chapter, has a few verses which state that if a man is ill or is diseased or is unable to give a child, the woman can marry, the second, the third and even fourth too and beget children from him. So is the case with a man for getting children. If he has no child from his first wife, he may marry the second woman; if not second, then the third one; and even the fourth one too. The first husband is named Som, the second one is called Gandharv, the third one is called Agni and the fourth one is called Manushya. The four wives are termed Somya, Gandharvee, Aagneyee and Maanushee.

This information, that Bhartrahari and Vikramaaditya were brothers, and Bhartrahari was born to a maidservant (Shoodra) is known in literature (see   Birth of Vaitaal), but their father's name does not match with "Chandravarn". There it is given as Gandharvsen.