The headstone of the grave of John Ystymllyn stands in the churchyard of the church of St Cynhaearn, on the north side of the path from the lychgate.   

John Ystymllyn, colloquially known as Jac Black, was captured as a child, probably in the West Indies in around 1742 by a member of the Wynne family and brought back to Wales to the nearby farm of Ystymllyn, from where he took his name. This may have been Mary Wynne who was married to William Hollier, possibly the same Hollier as secretary of the African Company of Merchants dealing in slave trade on the Gold Coast. 

He is said to be the first slave brought into North Wales. A portrait of him was painted in 1754 and is held at Plas Dinas. An engraving of the portrait is held at the National Library of Wales.   

It was fashionable at the time to have a black servant and John worked at Ystumllyn as a gardener, eventually being given his own house. He married Margaret Gruffydd and they had seven children.  

The simple sandstone headstone, erected posthumously, is elegantly inscribed with the inscription 'Here lieth the Body of John Ystymllyn who Died July the 27th 1791, Aged 46 Years', followed by the following englyn in Welsh:   

Yn India gynna’m ganwyd, a nghamrau 

Yng Nghymru'm bedyddiwyd   

wele’r fan dan lechan lwyd  

Du-oeraidd y'm daearwyd. 

[In India was the land of my birth, but I was baptised in Wales; this spot, marked by a grey slate, is my cold, dark resting place].

The headstone is grade II listed and described as of special interest in commemorating a slave in service in Wales in the later years of the 18th century, who must have been well enough thought of that he was provided with a handsome memorial and with an englyn composed by a locally well known poet, David John James. 

References:

Cadw listing description.

Friends of Friendless Churches: John Ystumllyn: From Africa to Ynyscynhaiarn