Manannán mac Lir, Manawydan fab Llŷr or Mannan beg mac y Leir is the most widely recognised son of Lir / Llŷr in the Blessed Isles. In mythological terms, the Irish Manannán is a sea deity while his Welsh counterpart Manawydan is simply a heroic figure. The Manx Mannan remains strong connections with the Irish deity but has a flavour of familiarity that seems to reduce the effect of the god belief somewhat. There are a number of tales associated with this character and he has been euhemerised under various names, which may actually indicate separate character of the same name who has been subsumed in the Manannán core or may indicate how widespread his god belief was once the Otherworld elements had become enshrined in folklore.
The Celtic Interpretation uses the following points to identify Manannán as a god-like figure that have been developed to explain positive Otherworld personalities or origins:
Association with the sea
Calling Manannán the son of Lir (or Llŷr, or Leir), is simply calling him the son of the sea. While Lir / Llŷr was later identified as a vague individual, the original usage merely reflects the Celtic tendency to describe Otherworld places as being beyond or below the waves. In effect, this is creating a conjectured ancestry for an Otherworld animal or their spirit form that had some positive interaction with someone from our reality in an era when ancestry and rank were considered extremely important.
Association with an Otherworld location
Manannán is generally identified as the ruler of Emain Ablach, or the Isle of Apples, the home of the Otherworld apple trees with silver branches and golden fruit that often call heroes to their adventures, whether imrama or echtrai. This is a strong association with the Otherworld and, although the modern location known as the Isle of Apples may not be identical with the historic or mythological locations, the descriptions are clearly identifiable as a specific location between Ireland, Scotland and Wales.
It is worth noting here that Emain Ablach was identified with the Isle of Arran as well as, more regularly, the Isle of Man, although these identifications were proven somewhat erroneous through Expeditionary research.
Traditionally, the Isle of Man has been considered to be named after Manannán (or Mannan in their own form of Gaelic). However, deeper study of the name of both god and island suggests that this is mistaken folk etymology with the god being named after the island, i.e. with Manannán roughly translating in modern terms as “Man from the Isle of Man”. However, due to the way stories accrete around single points, Manannán may actually be named after a different island.
The oldest forms of the Isle of Man’s name are Manaw, Manau or Mano with considerable overlap between the three referring languages of Irish, Manx and Welsh. The root appears to be an old word for “mountain”, would be a good description of the Isle of Man. Given that Anglesey has a similar etymology for its Welsh name, Ynys Môn, it may even be that there were several locations referred to as “Man” or “Mon” of which only the two in our reality have survived to be clearly identified. It is known that the lands of the Gododdin in South Scotland and Northern England were often referred to as Manaw Gododdin, leading to confusion in some stories and records. More on topic, Arran’s name may derive from a word for “high place”, which is not dissimilar for meaning and the place may have been referred to as “mountain” on some occasions or among certain people. It is also likely that some form of Manaw, Manau or Mano was used to refer to Emain Macha on occasion, leading to the confusion with the Isle of Man.