I have some more details, it`s actually in the parish of Llangwyfan. The OW initials mentioned are probably Owen Woode, I found the info below on a web site. It could be a MI on a very old gravestone ?.
1 The following scans in hexameters:-
“Blessed, thrice blessed, O marble, because you hold the noble Wood, which the unhappy island now misses. While alive, Owen was a useful wood to his homeland and after his death, he is the Wood of life [a play on lignum vitae, presumably] to God. I, his son, set up this monument to my father. This is my prayer, whose name is the same as yours, Owen. ”
The remainder reads “ On the death of Owen Woode, armigerous [ ie. bore a coat of arms] who died on the 6th day of April in the year of our Lord 1602 aged 70 .”
2 Llangwyfan House
From 1841 /1911 Llangwyfan Isaf was occupied by a succession of Owens , whether these are the same family I don`t know , there are so many Owens in the are it`s really hard to work out.
1841 Robert Owen 60.
1851 Richard Owen 43
Wife Ellin Owen 47
1861 Richard Owen 57
Wife Ellin Owen 55
1871 Richard Owen 57
Wife Judith Owen 27
1881 William Owen 36
Wife Elizabeth Owen 36
1891 William Owen 46
Wife Elizabeth Owen 46
1901 William Owen 56
Daughter Ellin Catherin Owen 24
One decade later
William Owen 66
Daughter E F Richards wid 31
Sister Margaret Roberts widow 71
Any more help still will be appreciated . Considering this is such an old building, there is very little on the web.