A marriage certificate is important because you can make sure that a couple you had been led to believe married each other actually had. For example if you find the marriage registration in the GRO Index, and believe the couple married each other, it is important to obtain a marriage certificate to confirm it. There are 2 or 3 marriages on each page in a church marriage register.
The first information stated is the year of marriage and the venue. The next detail is the entry number from the original marriage register from the venue.
This is followed by the marriage date and by the bride and groom's names and their ages. In earlier centuries, their ages may not have been recorded in full, it only stating whether they were of full age or a minor. If the term minor was used this meant they had not reached the age of 21 and had parental consent to marry, although sometimes the lady could add a few years on to her true age so she did not need to seek consent. The bride and groom signed the marriage certificate, and if they were illiterate, a cross was entered, signifying they had made their mark.
Further information provided is their marital status, it very often stating, especially in earlier centuries, whether they were spinster, bachelor, widower or widow. Sometimes, however, either party was not always truthful about their marital status if they wished to hide the fact they had been previously married. This was especially true in earlier centuries when divorce was looked on as being a great scandal and it cost so much to dissolve a marriage.
In earlier certificates of marriage the groom's occupation was stated, but the women’s occupation was very often not stated even if she did in fact work.
You can also find out the parties residences at the time of their marriage.
The fathers' names are mentioned on a marriage certificate, along with their occupations. If either father was deceased, this may be mentioned and could help in the search for their death date.
If either party was illegitimate the column for father’s name could be blank or he or she could have stated another family member was their father so it sometimes requires further research to prove his identity. I myself have found this to be the case in that my great-great grandfather’s brother, who being illegitimate, stated that his uncle was his father on his certificate of marriage.
The fact that the father's name is usually stated can help to further family tree research especially if the lady is a widow or was previously married because it may reveal her maiden name.
It also gives details of witnesses, who could be relatives of either party. These relatives could have been previously unknown to you. The witnesses could also be family friends. They have to sign marriage certificates.