Name: Sulis (Sulis Minerva)
Sphere of influence: Healing
Famous portraits: This one shown here, from Bath
This is the goddess that gave the city of Bath it's Roman name 'Aqua Sulis'. Much of what we know of her is from Roman times - but she was obviously an important Celtic deity before the Romans came along.
Her name has some connection with the word 'sun' and she is one of the most important Celtic water deities that we know of (though one should remember that there is a lot about Celtic religion we know precious little about). When the Romans encountered her they connected her with their own Minerva - or at least the healing-capacity of her. This makes her sometime called Sulis Minerva.
The mixture between Celtic and Roman when it comes to this goddess is also very obvious in the
cult statue that was made of her. She is a Celtic goddess, but the statue is classical. The head is the only thing that survives of it - it is on display in Bath (and can be seen here above). It is gilded bronze and at one time it even had a helmet, which is now lost.
She was seen mostly as a healing goddess, but at her shrine in Bath has been found tablets with wishes of assistance from devotees that did not always deal with health and she could for example be asked to help in revenging misdeeds done to the person asking for help - sometimes expressed with a very crude language. At the shrine in Bath several gods and goddesses were venerated, both Celtic and Roman - but Sulis was without a doubt the most important one. The Roman temple was built as early as sometime 60-75 AD.