From BiblePortal Wikipedia

Watson's Biblical & Theological Dictionary [1]

father of James the less,  Matthew 10:3;  Luke 6:15 . Alpheus was the husband of Mary, believed to have been sister to the mother of Christ; for which reason, James is called the Lord's brother; but the term brother is too general in its application to fix their relation though the fact is probable. Many are of opinion that Cleopas, mentioned  Luke 24:18 , is the same as Alpheus; Alpheus being his Greek name, and Cleopas his Hebrew, or Syriac name, according to the custom of this province, (or of the time,) where men often had two names; by one of which they were known to their friends and countrymen, by the other to the Romans or strangers.

2. ALPHEUS, father of Levi, or Matthew, whom Jesus took to be an Apostle and Evangelist,   Mark 2:14 .

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [2]

in Greek mythology, was a god of a river, the son of Oceanus and Tethys, famous for his love for the nymph Arethusa, who bathed in the river which he ruled over. She refused his proposal and fled, leaving her dress behind her. Alpheus was already close upon her, when she prayed to Diana, who covered her with a cloud. However, Alpheus followed the cloud, when it was suddenly changed into water. Alpheus now changed himself into his watery form and sought to mix his stream with hers, but Diana removed her to the island of Ortygia. Again Alpheus found a way to her, and Arethusa, not wishing to withstand such a passionate love, permitted him to mix his waves with hers. The ancients related some very wonderful things about these two streams. The Arethusa was said to become of a red color when the blood of the sacrifices at Olympia flowed into Alpheus. The latter is also said to have slain his brother, and in despair he threw himself into the Nyctimus River, which subsequently bore his name. The water was said to possess the virtue of giving to departed souls forgetfulness of all the past. The Alpheus River rises on the southern limit of Arcadia, and runs through Elis, in Peloponnesia.