The name is derived from the Welsh male name, Myrddin (sea fortress). It is borne in Arthurian legend by a renowned wizard, who was possibly based upon an amalgamation of a few historical figures, one inspiration being Myrddin Willt, a Welsh madman and prophet who lived in the Scottish forests. Another source of inspiration may have been Roman military leader, Ambrosius Aurelianus .
It is believed that Geoffrey of Monmouth Latinized the name as Merlinus instead of Merdinus due to the latter’s close similarity to the Norman French word merde (excrement).
The name was never very common in the English-speaking world and only seems to have recently caught on. It is currently the 350th most popular male name in Germany, (2011) and the 427th most popular in France, (2009).
It is also the name of a type of bird.