"... The term "common-law marriage" is a misnomer because it refers to a "law of marriage" which we supposedly inherited from England when we adopted its common law on July 4, 1776 [see the www site for all footnotes] This is because there was no common law of marriage in England on July 4, 1776. The early Anglo-Saxon form of marriage involved a betrothal, by which the bride's father or relatives agreed to
transfer the "mund," or custody for protection, of the bride to the bridegroom. In return the bridegroom agreed to make a transfer of property to them, or make a settlement of property upon the bride, and, in addition, to care for and protect her. Following the betrothal, the bride's family delivered the bride to the groom, who made the promised settlement in return. After the Norman Conquest, the power to regulate marriage was given to the Church and the ceremony took place in the presence of a priest. The wedding ring was given as a pledge that the bridegroom would perform his covenants. The additional ecclesiastical requirement of thrice publishing the banns for all church marriages was imposed and marriages had to be conducted in church and by a priest.
When the English Reformation transformed the Roman Church and ecclesiastical establishment into an English church, the marriage ceremony and the church's requirements did not change. However, the Church was willing to recognize two kinds of informal marriage, known as "sponsalia per verba de praesenti" and "sponsalia per verba de futuro." The first took place when the parties exchanged promises that they would be man and wife from that moment on. The second required an exchange of promises to be man and wife in the future, followed by sexual intercourse. When the parties presently took each other as man and wife, a valid marriage was formed. Consummation was not required. In the case of the promise to marry in the future, a valid marriage resulted only when the parties consummated their promise by intercourse.
Until the middle of the eighteenth century these informal marriages were held valid by the ecclesiastics who had the jurisdiction to determine the validity of a marriage.
In 1753 Lord Hardwicke's Act required a parish church ceremony in the Church of England, publication of banns, and a license as a condition to the validity of a marriage. The purpose of the Act was to prevent clandestine marriages, "Fleet" marriages and other fraudulent or irregular marriages. The Act governed only marriages contracted in England, leaving Scottish and Irish marriages subject to the earlier rules allowing informal marriage, and did not apply to Quakers and Jews.
In the American colonies marriage was regulated by the civil authorities, and informal marriages were recognized as valid, at least in the absence of a statute requiring a ceremony. This enabled parties, such as the pioneers, to contract valid marriages when there was no clergyman or civil officer available to perform a ceremony.
English law also recognized several impediments to the formation of valid informal and formal marriages. A close relationship between the parties, either by blood or marriage, was a reason for declaring the marriage invalid. The range of the relationship which disqualified the parties from marrying was narrowed in the early sixteenth century, after the Reformation, to the Levitical degrees.
Infancy was also an impediment to marriage. Children below the age of seven were incapable of marrying. After the age of seven they might marry, but the marriage was voidable until they were able to consummate the marriage, which the law presumed to be at age fourteen for boys and twelve for girls. Beyond those ages the marriages were valid, even though the parties were under the age of twenty-one and did not have their parents' consent. Later statutes imposed the requirement of parents' consent.
The English method of entering into an informal marriage, known as "sponsalia per verba de paesenti", was adopted in New York. Its legal definition of a common-law marriage is an agreement, in words of the present tense, made by parties competent to marry, to take one another as husband and wife. Ordinarily, common-law marriages are unlicensed. Cohabitation, repute, holding out, and the like generally are regarded as bits of evidence which are more or less cogent in showing that such an agreement, in fact, was made, but they are not a substitute for or the equivalent of the actual agreement.
Common-law marriages were abolished in New York on April 29, 1933, as the result of an amendment to Section 11 of the Domestic Relations Law, which enumerated the persons by whom marriages must be solemnized. Prior to that date, common-law marriages were generally recognized as valid if entered into in this state, with the exception of the period between January 1, 1902, and January 1, 1908, when such marriages were rendered invalid by statute.
While common-law marriages were abolished in New York on April 29, 1933, common-law marriages contracted prior to that date and at a time when such marriages were valid in New York, are as valid as ceremonial marriages, and the long standing rule of conflicts of law is that recognition will be given by New York to a common-law marriage that is valid at the place where it was contracted. Currently, 13 states and the District of Columbia permit common-law marriages to be entered into within their borders, although such states differ as to requirements of proof...."

Excerpted from  http://www.brandeslaw.com/clmart.htm