Elias 1 is from the Hebrew Bible. Elijah and Elias are used to describe the same person, with Elijah being Hebrew and Elias being Greek. The prophet Elijah (1 Kings 16:29 to 2 Kings 2:18) practiced his ministry in Israel during the reigns of King Ahab (874-853 BC) and his son King Abaziah (853-852 BC). Elijah, a Tishbite from the region of Gilead, was a prophet in Israel during the reigns of Ahab, Ahaziah and Jehoram. All his life Elijah was active in the defense of God. His teachings brought him into constant conflict with the Kings of Israel, and on one occasion had to flee for his life. He fought against the cult of Baal, and clashed frequently with Ahab's wife Jezebel, who had introduced the pagan cult in Israel. The New Testament uses Elias in reference to the Old Testament Elijah. The above was taken from here and here and much more information can be found here.
Elias 2 is the Oratorio by Felix Mendelssohn Bartholdy. I had the pleasure of hearing a performance of the oratorio last Saturday evening at Peterskirche. Information about the program can be seen here and here, information regarding the choir here, and about the orchestra, here.
As some of you know, Elias 3 is the most "important" Elias. Elias Swartzendruber Moyer is our grandson, son of Jonathan and Rachel Moyer, and here is Flying Elias: