Thomas Roberts, who was born in Waterford, was the most talented and shortest lived Irish landscape painter of the second half of the eighteenth century. He had entered the Dublin Society schools as a boy in 1763 and was taught by the landscape painter James Mannin, and afterwards worked under George Mullins as an apprentice when the latter was working in his home town of Waterford, later following him to Dublin where they lived in the same house for a time. By 1766 Roberts was exhibiting at the Dublin Society of Artists, where he was to send some fifty-six works before his untimely death from consumption; he soon established a reputation as an outstanding talent whose services were in great demand especially for topographical paintings.
This picture shows the weir on the River Liffey in the demesne of Lucan House, Co. Dublin, which lies to the west of the house. At the time that this picture was painted Lucan House belonged to Agmondisham Vesey, M.P., who was Accountant General of Ireland and a member of Dr. Johnson's circle. The house stood on the site of a castle built in the twelfth century which had belonged to the Earls of Kildare but which by 1564 was in the hands of the Sarsfield family. Patrick Sarsfield, one of King James II's most valiant soldiers, was created Earl of Lucan in 1691 and followed his monarch to France after the treaty of Limerick. The house and estate came into the possession of the Vesey family through the marriage of Patrick Sarsfield's niece and heiress, Charlotte, to Agmondisham Vesey, the father of the Agmondisham Vesey who employed Roberts.
Agmondisham Vesey, M.P., commissioned Roberts to supply a set of four pictures of Lucan House and its demesne, circa 1773-5, which is now in the National Gallery of Ireland (see N. Figgis and B. Rooney, op.cit., pp.408-414, nos. 4463-4466). One of the pictures in this set shows the old gothic house which Vesey was to pull down and replace with a Palladian villa nearby (now the official residence of the Italian Ambassador to Ireland) shortly after Roberts painted his view. The present picture shows the weir which lies half way between Lucan and Leixlip which, with its distinctive flat rock was a notable feature of the demesne. Lucan Demesne originally ran westwards between the river and the road on the right bank of the River Liffey virtually as far as Leixlip, Co. Kildare, with a similar amount of land on the left bank. The weir evidently fascinated Roberts and it features in three of the four views in the National Gallery of Ireland. The present picture is virtually identical to one of the views of the weir in the National Gallery set and is of the same format. Figgis and Rooney (op.cit.) comment of the present picture that 'Instead of two men conversing by the bank, as one sees in the NGI picture, a courting couple sit under a tree ... The similarity between these two paintings means that it is impossible to ascertain after which Thomas Milton produced his engraving, published on 1 January 1787, or if it was based on yet another version of the same subject'. It is has been suggested that the two figures in the foreground of the picture may represent Agmondisham Vesey and his wife. The figures in the foreground show the influence of the work of Thomas Gainsborough which Roberts may well have seen while in London and Bath in 1775 and 1776.
The present picture remained in the artist's possession and afterwards in that of his family until it was sold in 1981.