"It is the most natural thing in the world that there should be certain blendings, compromises, and points of affinity between the Stregheria - witchcraft, or "old religion", founded on the Etruscan or Roman mythology and rites - and the Roman Catholic: both were based on magic, both used fetishes, amulets, incantations, and had recourse to spirits. In some cases these Christian spirits or saints corresponded with, and were actually derived from, the same source as the heathen. The sorcerers among the Tuscan peasantry were not slow to perceive this."

Quote from Etruscan Roman Remains (1892) by Charles Leland  

In Italy it has long been the custom, since even the Middle Ages, for Italian witches to cover their identity with a veneer of Catholicism so as not to draw suspicion. This includes attending Mass and participating in the Rites of Passage expected of one in the Catholic community.   Charles Leland, in his book Etruscan Magic & Occult Remedies, records the old connection between Witches and Catholicism, of which he writes: 

"As for families in which stregeria, or a knowledge of charms, old traditions and songs is preserved, they do not among themselves pretend to be even Christian. That is to say, they maintain outward observances, and bring the children up as Catholics, and "keep in" with the priest, but as the children grow older, if any aptitude is observed in them for sorcery, some old grandmother or aunt takes them in hand, and initiates them into the ancient faith." 

Much of their magic appears mixed with Catholic rites and saints, the origins of which date back to ancient times. Certain saints such as Anthony, Simon, and Elisha are viewed as demi-gods and their magical rites of evocation are performed in cellars. Leland mentions in the introduction to Etruscan Roman Remains, a conversation he had with a Strega woman, she says:

"I call myself Catholic - oh yes - and I wear a medal to prove it" - here she, in excitement, pulled from her bosom a saint's medal - "but I believe in none of it all. You know what I believe." (Leland responds) "Si, la vecchia religione (the old faith), I answered, by which faith I meant that strange, diluted old Etrusco-Roman sorcery which is set forth in this book. Magic was her real religion."

A distinction needs to be made between Stregoneria and Stregheria.  Stregoneria is a folk magic tradition that embraces the Christian elements and works within that theology.  In other words, they are practitioners of magic in a Christian system.  By contrast, Stregheria is Pagan at its core and understands that the practice of saint magic, and in the inclusion of Catholic religious items, are for show only.  Even though both words (stregoneria and stregheria) are translated in English as Witchcraft, this is false in terms of what each system actually represents.  Stregheria is Witchcraft, a pre-Christian tradition.  Stregoneria is a form of sorcery used in Catholic-rooted folk magic traditions.

EXCERPT FROM WAYS OF THE STREGA by Raven Grimassi:

Many modern Strega simply consider Catholics to be Pagans who have accepted the divinity of Jesus. There are some interesting concepts in both the Old and New Testaments which resemble Strega beliefs and may well be the foundation of such a concept. According to the New Testament the Magi were the first to seek out Jesus after "seeing" his star. Legend claims that they were astrologers and associates them with the lands of Chaldea, Egypt and Persia. These are all places that have an occult history dating far back into antiquity.

The tale of the Magi recorded in the book of Matthew seems to indicate that these mystic Pagans were among the first to go and pay homage to Jesus. In the book of proverbs (chapter 8, verse 2) we find a personage called "wisdom" conceived of in the form of a female divinity who "stands at the crossroads" (a phrase used in ancient times concerning the witches' goddess.) Wisdom speaks of being present both prior to and during the process of Creation. In verse 30 (The Jerusalem Bible) she claims to have been God's assistant during the process of Creation:  "I was by his side, a master Craftsman, delighting him day after day, ever at play in his presence, at play everywhere in his world, delighting to be with the sons of men."

In the book of Wisdom (found only in the Catholic version), "wisdom" is praised with these words (chapter 7: 22-27): "For within her is a spirit intelligent, holy...penetrating all intelligent, pure and most subtle spirits; for Wisdom is quicker to move than any motion; she is so pure, she pervades and permeates all things...She is a reflection of the eternal light, untarnished mirror of God's active power...although alone, she can do all; herself unchanging, she makes all things new..." 

Connected to this concept of the feminine aspect of Divinity is the word ruach. In Hebrew this word is of feminine gender and would properly be defined in the sense of feminine divinity. When we read in the account of Creation (Book of Genesis) that the "spirit of God moved upon the face of the waters" the Hebrew word used here for spirit was ruach. In the New Testament this has been translated into "Holy Spirit" as in the Trinity concept of "Father, Son, and Holy Spirit."

Hebrew mystics of the Kabbalah considered ruach to be associated with the element of air and thus with spirit as well. Among early Kabbalists the sound of a word denoted its elemental association; soft sounds were associated with air, hard sounds with earth, hissing sounds with fire and muted sounds with water.  It is not necessary, however, to look to Catholicism in order to find remnants of earlier pagan worship. Aspects of Stregheria still survive today in both Italy and America, even among those who would not readily identify themselves as being members of La Vecchia Religione. They employ various prayers to a host of saints, lighting candles and placing assorted objects as required by tradition. Saints such as St. Anthony, St. Jude, St. Anna, and St. Simon have replaced the old pagan gods to whom similar prayers and offerings were once made.