Ages at Census are very often incorrect so you can't be sure of exactly when a person had been born. The information on the census is only as good as the person supplying the information on who slept in his house at midnight on census night. If he couldn't remember the birth years or ages of everyone in the house on that night then you get wrong ages and possibly wrong birth places too. If Maria was 14 in the 1861 then she would only be about 4 in the 1851. I think she is a different person to Mary who probably had died by the 1861 and then another daughter called Mary was born 8 years or so before the 1871. You need to check the PRs perhaps for burials for the places where the family lived from census to census to see if you can find a burial, and perhaps her baptism too, for the daughter Mary and also check for the baptism of Maria. With such a common name of Brown it would be hard to find the right Mary Brown in the GRO index as you will know already. Perhaps William the head of the household was not the person filling out the schedule for the 1861 and 1851 censuses, maybe it was his wife filling out the schedule or giving the information to the enumerator who wrote it down. Mary, the wife, might have given her husband's age worked out from her own, maybe she wasn't aware of exactly how old her husband was why would she be concerned about his age. People didn't seem to be so preoccupied about ages and such details back then. William was probably at work down the coal mine when the enumerator called with his questions and schedule. In the 1871 it could be that William himself was around to give his own information. Regards Jenny DeAngelis. Spain. Hi, I wonder if anybody can help me solve a mystery. I detail below matrix of the 1851 to 1871 census returns for my past family:- Newfield 1851 Census - Byers Green - Seldom Seen William Brown Head 29 Coalminer Bedfordshire Mary Brown (mn ?) Wife 28 Durham Mary Brown Daughter 11 Durham Helmington Row 1861 Census - Bowden Close William Brown Head 38 Coalminer Elstow Bedfordshire Mary Brown (mn ?) Wife 38 Stanhope Durham Maria Brown Daughter 14 Wolsingham Durham Tudhoe 1871 Census - Mount Pleasant, 37 Pit Row William Brown Head 55 Coalminer Elstow Bedfordshire Mary Brown (mn ?) Wife 49 Stanhope Durham Mary Brown Daughter 8 Scholar Fylands Bridge Durham My queries are:- 1) Is Mary (1851) and Maria (1861) one of the same person and has her age been recorded incorrectly. Although it is quite clear on the 1851 census return as 11. 2) If they are different people, where was Maria in 1851 3) The marriage of William and Mary has got me stumped - the 1851 & 1861 census make William's birth year c.1822 whilst 1871 gives him a birth year c.1816. There is a marriage of a William Brown recorded in the second quarter of 1840 in Auckland. Am awaiting receipt of the Marriage Certificate.