According to Heritage England, parts of St Senara’s Church, such as the south wall, date back to the twelfth century, whilst the chancel dates to around the thirteenth or fourteenth centuries.  The church was not majorly altered until a partial rebuild took place in the late nineteenth century. This involved a new roof, stripping the walls of plaster and new fittings, such as pews.  It is in this condition that the church exists today.
A particularly insightful article on St Senara’s Church was published in the Royal Cornwall Gazette, on 9 August 1878. The article, written initially to the Church Review under the heading ‘Zennor Church, near Penzance’, advises readers that a visit to Zennor Church is unmissable, with it being set in “wild and romantic scenery”.
However the writer’s impressions of the church’s interior were less idealistic. It appears from this article that during the late nineteenth century, the Church’s condition had greatly deteriorated. Within the article, the pews are described as “facing all points of the compass”, and that the “only tolerably decent seat in the Church belonged to the vicar”.  When comparing this perspective to the information provided by Historic England, the partial rebuild of the church which occurred in the late nineteenth century must have taken place shortly after the publication of this article in 1878.
The restoration of St Senara’s Church during the Victorian period is described in an article printed in the Cornishman on 28 November 1889. The church itself is described as
“a much dilapidated and nearly ruinous sanctuary”.
Works required, which included a new roof, were estimated to cost at least £1,300, which with inflation would amount to £164,095.45 today. The parish community came together to raise this sum through individual donations, including £250 each from the Reverend Borlase and a Mr Westlake Q.C. of Eagles Nest.  A summer bazaar was organised to raise the funds, with the sale of jewellery, flowers, dresses and vegetables, all donated by members of the community.  The restoration work was completed by December 1890, with the work by Cornish church-builders Carah and Edwards being described as
“most effectively carried out”.
Myth & legends
One significant maritime aspect of Zennor Church is the case of the ‘Mermaid of Zennor’. In the distant past, the Cornish people believed in the existence of mermaids, which were considered to be a combination of human kind and maritime species. Within the 13 September 1883 edition of The Cornishman, a description of the Mermaid of Zennor is written, provided by then reverend of Zennor, W S Lach-Szyrma. His interpretation was that the Mermaid of Zennor was “a mere, old world superstition, a heathen invention or myth”, however the article highlights the fact that its origins may extend back to the early Christian Church. 
The Mermaid of Zennor is significant as it demonstrates the link between human life and marine life, a connection which is particularly strong for the fishing and seafaring communities of West Cornwall. The legend has altered over the years, with another belief being that the choir of St Senara’s Church were so enchanting with their singing that the mermaids were induced to come up from the cove below the village to listen to the music.  The legend claims that a an especially beautiful lady came into the church, a mermaid, and prevailed a young man, Mathey Trewhella, to follow her back down to the cove. In the cove he met the fate of most young men who were captivated by the mermaid’s beauty, who were drowned. This also led to an interesting study on the development of error during the late nineteenth century. 
Carved into a pew in Zennor Church is the figure of a mermaid, this is related to another alternation of the mermaid legend. Many years after the disappearance of Mathey Trewhella, a ship dropped anchor off Zennor Cove, when the captain heard a beautiful voice, followed by the sight of the mermaid herself.  Sailors fear that mermaids will bring bad luck, and thus, the captain raised his anchor and went ashore at Zennor to inform the people of Mathey Trewhella’s fate. In memorial to Mathey Trewhella, and to warn other men against the temptation of the mermaids, the figure of the mermaid was carved into the church pew.