Trim Castle was built towards the close of the twelfth century by Hugo de Lacy, the greatest castle builder ever the Anglo-French produced. He built the great castle at Clonmacnois, which has been already described. He built another fine one in Carlow, and was building the castle of Durrow, in the King's County, when a young Irishman, who had evidently come prepared to kill him, struck off his head with a blow of an axe as he was stooping down to examine the work. If Hugo de Lacy had not been killed, he would certainly have built many more castles, not only in the English Pale, but throughout Ireland. But Trim Castle was the finest structure of its kind that he ever raised. Lewis' Irish Topography says that the Castle of Trim was built in 1220. This is just such a mistake as one would expect to find in books like it, Hall's, and others of their kind, which were written by persons almost wholly unacquainted with the history of the country about which they wrote, and entirely unacquainted with its language and native literature. Trim Castle must have been built before 1186, for Hugo de Lacy was killed in that year. The same extraordinary publication says that Trim was burned by Connor O'Melaghlin in 1108, and that over two hundred people were burned in the monastery. It would be interesting to know where Lewis got his information about this matter. He did not get it from any authentic source, for the annals of the Four Masters, the annals of Clonmacnois, the annals of Inisfallan, the annals of Ulster, and the _Chronicon Scottorum_ are all silent about it.