From the St Ives tourist association website:
“St Ives enters recorded history with the arrival of St. Ia or Hya, the Irish princess who introduced Christianity to the area in the 5th Century.
The legend tells how Saint Ia, a Virgin Saint of noble birth went to the seashore to depart for Cornwall from her native Ireland along with other saints. Finding that they had gone without her and fearing that she was too young to undertake such a hazardous journey alone, she was grief stricken and began to pray.
As she prayed she noticed a little leaf floating on the water and touched it with a rod to see if it would sink. Lo, as she looked it grew bigger and bigger. Taking this as a sign from God, she climbed aboard the leaf and was straightaway wafted across the Channel, reaching her destination well before the others.”
Umbrellage 