The Parish Church was founded in the 12th Century by a Norman Knight, Simon Loccard. It belonged to the Trinitarian Monastery at Failford (just outside Mauchline). The Church was restored in the 18th Century and again in 1919. Whilst doing this restoration it was discovered that the earlier work had covered up some marvellous architectural features, including an open-work timber roof.
"The church of Symington or Symonstoun is undoubtedly very ancient, being mentioned in old records as one of the five parish churches in Kyle belonging to the convent of Fail. The style of the windows indicates the 13th century. It received an addition and alterations in 1797, which, while increasing the accommodation of the building, detracted considerably from the uniqueness of its appearance. The church continued to be a vicarage until the Reformation, after which period the patronage passed through several hands and was at length acquired by the Earl of Eglinton."
"In the churchyard there are many old tombstones. One of these, now standing against the vestry wall, and which may have marked off, at one time the grave of a martyr, has inscribed upon it the following words, on the top of the stone: 'James M'llwyen, Marter by Clavers, 1665', and on the front of the stone, 'Heir lyis the corps of John Macklwyen, who departed the 29th of March, 1703'. The top inscription may have been an afterthought, with mistake as to date, as Claverhouse was born in 1650, and would be only fifteen years of age at that date."
"Ayrshire Nights Entertainment: A Descriptive Guide to the History, Traditions, Antiquities of the County of Ayr" by John MacIntosh of Galston, Ayrshire, published in 1894, by John Menzies & Co. of Kilmarnock, Dunlop and Drennan.