Preece Family Tree

John Key appears to have married two women both called Mary Martyn.

The only marriages of a John Key (or variants) to a Mary (any surname) in Cornwall in the relevant time period are:

17 May 1807 John Key and Mary Martyn
26 Dec 1829 John Key and Mary Martyn

So we can be sure that the John and Mary Key on the 1841 and 1851 Census are one of these couples.

The 1841 Census doesn't show any other family members; the 1851 Census shows a William Rogers, visitor. Jane Key, daughter of John and Mary Key bap 31 March 1809, married a Thomas Rogers, who had a brother William of the right age and birthplace to be the William Rogers on this census record. This suggests that we are probably looking at the same John Key who was the father of Jane. If so, then Jane's mother must be the Mary Martyn of the 1807 marriage - but not necessarily the same Mary that is married to John by the time of the census.

Furthermore, the two marriages mentioned above are the only marriages of a Mary Martyn (or variants) to anyone with the surname Key (or variants) in Cornwall in the time period.

There are three Mary Martyns baptised in St Stephen-in-Brannel of the right age to be John's wife:

22 April 1781, daughter of James and Grace
20 March 1791, daughter of Susanna
4 April 1800, daughter of Thomas and Alice - born about 1784

Looking now at burials in St Stephen-in-Brannel - there is one burial of a Mary Martyn on 8 May 1782. No age is given, but as we haven't found any other Mary Martyns in the area in the period, she must be the 1781 baptism.

Similarly there is one burial of a Mary Key, on 30 May 1822, age 38. This would correspond to the 1800 baptism / 1784 birth. Futhermore, the evidence of Thomas Martyn's will suggests that his daughter Mary was deceased by 1830.

There's no burial records for a Mary Key after 1851, but we can look at the GRO death index for the district of St Austell, and we find the following two possibilities:

Q4 1864, age 74 (born about 1790)
Q1 1871, age 74 (born about 1797)

The first of these is a good match for the 1791 baptism.

Now on the question of whether it's the same John Key that married both Mary Martyns - we suspect it is true based on the evidence of the 1851 Census, but can we prove it?

Firstly we know that the John Key on the census records was born in St Stephen-in-Brannel around 1780. There are no matching baptism records in St Stephen in that year, but there is a baptism for a John Kay in the neighbouring parish of Roche, showing that the parents were sojourners - ie, not from Roche. This is the only plausible baptism for this John Key.

The only other two baptisms of John Key (or variant) in the area and of an age to have married Mary in either 1807 or 1829 are as follows:

John Kay, 10 May 1790, son of John and Grace
John Kay, 2 April 1792, son of John and Grace

As they have the same parents, it's likely that the first died in infancy - and indeed we find a burial record for an infant John Kay in 1790. So the only possible match is the John Kay of 1792.

The only other matching burial in St Stephen is a John Key on 8 November 1801, although unfortunately with no age indicated. Census records show that no other John Key born in St Stephen survived until 1851, and as there don't appear to be any other John Keys living in the area at the time, I think it is likely that this burial is the John Kay born in 1792.

Therefore I think that we've excluded all other plausible candidates of John Key, and along with the relationship implied by the 1851 Census, I think we can reasonably say that it is indeed the same John Key.

So we can therefore conclude:

- Mary Martyn born 1784 and baptised 1800 married John Key in 1807 and died in 1822.
- Mary Martyn born 1791 married John Key in 1829 and died in 1864.
- It is the same John Key in both marriages.