Once upon a time, Arethusa, one of the nymphs of old Achaia, was a bit stout but nonetheless beautiful. Just like a country girl, she blushed at her generous physical endowments, and did not care at all for her beauty.
After visiting the Stymphal fan woods, Arethusa was returning tired, when she saw a stream of clear water that flowed smoothly, without any ripple or sound, almost seeming as if not moving at all. Hesitatingly, she touched the stream with her feet, and then ventured deeper to her knees. Finding it pleasant, she removed her robes and plunged deeply in the stream, to enjoy a cool swim.
While swimming, she heard a strange sound coming from the stream, and in alarm, she swam to the nearest bank. Standing on the bank, she heard the river-god Alpheus question where had she hastened. Terrified, she fled naked, as her robes were on the opposite bank. When Alpheus saw her fleeing naked, it inflamed him all the more, and quickly changing to a human form, he swiftly chased her, just like a hawk pursues a trembling dove. Arethusa ran for a long time with Alpheus hot on her heels, until overcome with fatigue and desperation, she cried for help to the chaste goddess Diana. Taking pity, Diana enveloped her in a dense cloud. The baffled Alpheus, twice circled the cloud and twice called her name.
Within the cloud, Arethusa felt just like a tremulous lamb, who although is within a high fence, yet trembles upon hearing wolves howling nearby. Alpheus, finding no footprints of her escape, did not depart. The besieged Arethusa, began to sweat so profusely that she dissolved into flowing streams. Alpheus recognized the streams, and changed his form to his watery self, so that his waters may mingle with her streams. Seeing this, Diana made an opening in the ground, through which Arethusa plunged and escaped. She passed by dark Stygian streams and arose on the isle of Ortygia, as the sacred spring Arethusa.
Excerpt from the book “Once Upon A Time-II: 150 Greek Mythology Stories” by Rajen Jani