S Elias, Omnium Carmelitarum Dux et Pater

In the Carmelite Calendar today is the feast of St Elias the Prophet, the Father of the Carmelite Order. You can find most of what you need to know about Elias in the third book of Kings (if you're using the Douay-Rheims, the Knox, or any of the other scriptural translations that devolve from the old Vulgate) or the 1st book of Kings (if you're using the KJV, the RSV or similar).

In the Medieval era he was considered well and truly the Founder of the Carmelite Order and the Carmelites the descendants of the sons of the prophets. These days academia likes to have that sort of claim more clearly documented - preferably notarized - so the claim is today a spiritual descent since the Order originated in a place where he lived and had one of his significant triumphs.

A Vesper hymn from the old office:

The lofty peaks of Carmel
With tuneful praises ring,
The anthems of Elias
'Tis our delight to sing.

The glory of our Order,
Our leader, prop, and stay,
From east to west his offspring
Increaseth day by day.

When sorely pressed with famine,
A raven served him bread,
With meal and cruse unfailing,
The widowed hearth was fed.

The boy from death delivered
Is to his home restored,
And light so much desired,
In radiant flood is poured.

Behold the Heaven closeth,
To open at his voice,
And copious welcome showers
The thirsty lands rejoice.

To Father, Son, and Spirit,
Be equal power and praise,
All glory and dominion
Henceforth for endless days. Amen.

A collect:

Almighty God, grant, we beseech Thee, that we who believe that the Blessed Elias, Thy Prophet and our Father, hath been, in a wonderful manner, taken up in a fiery chariot, may, through his mediation, be borne upwards to Heaven, and that we may rejoice in the companionship of Thy saints. Through our Lord. Amen.

[from "The Saints of Carmel" (1896)]