One author which I came across, Henry A. Walsh, Ed.D, claims that the Catholic Church instituted celibacy for power - including political and economic power:
"POLITICAL POWER
The first known public discussion of celibacy occurred at the Council of Elvira in 309. Elvira was a regional council with no universal clout. When we place the canons of Elvira side by side with the canons of other councils in that same century (Neocaesarea 314; Nicea One 325; Laodicea 352) we wonder if celibacy, as we know it, was the primary interest of these councils at all. It would appear, rather, that these councils were attempting to correct clerical abuses, principally the practice of priests having mistresses. Neocaesarea and Laodicea, for instance, OBLIGED priests TO MARRY virgins, and to dismiss unfaithful wives.
Two historically prominent councils (Carthage Three and Carthage Four 397 AD - 398 AD) had nothing to say about celibacy. So, while Elvira is fingered as the council that opened the celibacy debate, Carthage Five in 401 was really the first council with universal representation that took a position on celibacy. This council suggested that priests separate from their wives and live as celibates. The operative word here is "suggested." Since no penalties were attached for noncompliance. The decree was seen as a recommendation and was ignored by most. Anyhow, just nineteen years after Carthage Five's "suggestion," we find Pope Honorius in 420 praising the wives who supported their priest-husbands in their ministry. (Lea, 1966 p. 33 ff.).
For the next four hundred years or so, various councils and popes attempted to establish MANDATORY celibacy, but with only partial success. It didn't help the cause of those advocating celibacy when a married man became Pope Adrian the Second in 867 A.D. (Lawrence, 1989, p.142). According to Christopher Brooke, 'The Norman clergy were the most resistant to the abolition of clerical marriage". (Brooke, 1971 p. 84). Henry Charles Lea offers many instances of the brutality inflicted on priests and their wives when Rome succeeded in getting some feudal lords to fine, imprison, even starve to death, priests who refused to dismiss their wives, and how the wives of priests were humiliated and reduced to abject poverty. (Lea, p. 99 ff.).
For our purposes here, we have a particular interest in Christmas Day 800 A.D., for on that day the surprised King of the Franks, Charlemagne, was coerced into kneeling before Pope Leo the Third who placed the Emperor's crown on his head. (Napoleon Bonaparte would later snatch the crown out of the pope's hand and crown himself). Pope Leo's gesture was a symbolic proclamation that the pope of Rome saw himself as an equal with the Emperor of the "Holy Roman Empire." The Church had proclaimed itself a political force to be reckoned with.
We see a great significance in this event because it positions the Church as a political power on the continent and prepared for what have come to be known as the 'Gregorian Reforms' of the eleventh and twelfth centuries. One of those reforms was the insistence on clerical celibacy and Rome now had political muscles to flex for the implementation of its decrees. "Clerical marriage," writes Raymond Lawrence Jr., "fell victim to the program of centralizing ecclesiastical power." (Lawrence, p.143). Anne Barstow says: "Ultimately, virtually every priest in the Western Church was separated from the economic and political ties of family inheritance and local politics and incorporated into a powerful international bureaucracy centered in Rome." (Barstow, 1982 p.157).
What might at first sight seem like a minor in-house event signaled, in fact, a major political tussle as Rome moved with deliberate speed to consolidate its political power. In 1059 Pope Nicholas the Second limited control over the election of a pope to the elite House of Cardinals. This led to a mighty struggle when Rome followed up by asserting its absolute authority over the appointment of all bishops. Up to that time, secular potentates exercised considerable influence over ecclesiastical appointments, often promoting their friends to positions of authority in the Church. With the signing of the Concordat of Worms in 1122, Emperor Henry the Fifth surrendered all influence over the appointment of bishops. Rome had so succeeded in centralizing power that, some seventy years after the signing of the Concordat, Pope Innocent the Third was in a position to issue his famous "Moon and Sun" proclamation, stating that civil authorities received their power from the pope, just as the moon received its light from the sun. (1198 A.D.)
By the twelfth century, Rome had also gained control over marriage. At first, it was to the benefit of women that Rome involved itself in the marriage scene, according to Erwin Haeberle, because Christianity changed the "rather barbaric customs that treated women little better than domestic slaves," and "endowed a rather prosaic arrangement with a new dignity." (Haeberle, 1981 p. 433). But, with time, marriage came under the control of the papal bureaucracy. Decisions about who could marry and who could divorce had been taken out the hands of civil courts and came to be vested in the hands of the papal tribunal. By the twelfth century, Rome was pronouncing on the validity or invalidity of all marriages, whether they involved potentates or peasants. Priests had become the official presiders at weddings. It was yet another coup for Rome in its drive for power.
With secular powers reduced to equals or subordinates, with control over all ecclesiastical appointments, with the power of final decision over the validity or invalidity of marriages in its hands, Rome was now in a very strong position to insist on MANDATORY celibacy for the ordained. At the Second Lateran Council in 1139, Pope Innocent the Second pronounced all clerical marriages invalid and the children of such marriages bastards. (Lea p. 264).
Thus, the first pillar on which the law of MANDATORY celibacy was to rest had been driven into the ground - the pillar of papal political power. As individuals who opposed the law of celibacy were to discover - Siegfried, Archbishop of Mainz, for example (1076) - opposing the new might of Rome was political suicide resulting in the individual's removal from office and excommunication. (Barstow, p. 69). Control over the personal and professional lives of its priests by means of the law of MANDATORY celibacy, coupled with all the other power that had been garnered, perverted the mission of the Church. Called to serve, it came to rule.
ECONOMIC POWER
By the twelfth century, as we have illustrated, Rome had consolidated an enormous amount of power in itself. For the most part, however, it was "paper power," the power flowing from signed concordats, papal pronouncements, decrees of its marriage tribunal, and so forth. To make that power more "real" Rome needed real estate. Many bishops were living like feudal lords, owning large tracts of land, and the priesthood was frequently passed on from father to son as an inheritance. Part of that inheritance was land, often given as "a benefice" to the local bishop or priest by a rich patron. Rome saw a possible bonanza here, if it could find a way to get its hands on all that real estate. Celibacy was the key. The inheritance lines had to be cut. That would bring all benefices under the control of the Church's bureaucracy and the appropriated lands could be leased out to fatten the papal coffers. Celibacy made Rome an important power broker in the real estate business.
Secular powers, too, recognized that celibacy could benefit them. Anne Barstow recounts a typical arrangement entered into by the Church and a secular power. When the bishop of Flanders opposed the law of celibacy, Rome released Robert, Count of Flanders, from obedience to the bishop. Thus undercut by Rome, the bishop was at the Count's mercy. Robert moved against the bishop and seized all his land. He also moved against priests who supported their bishop. Their property was also seized. The Count made "an offering" to Rome out of the money collected from leases and taxes. (Barstow, p. 31)
With celibacy fairly well established, Rome was now in possession of countless benefices. Riches poured into its coffers. Celibacy had given Rome economic power. But, as Martin E. Marty points out, Rome had to pay a high price for its new economic power because it "weakened the spiritual vitality and potential for holiness in the institution ... Perverted power repeatedly led to scandal and fall in the papacy. The combination of extravagant claims and extravagant incomes with extravagant papal personalities fattened the office for scandal." (Marty, 1959. pp. 191, 192).
Local bishops and local priests felt powerless in the face of an authority that wielded great political power, had the resources to enforce its decrees and was able to manipulate secular powers to carry out its demands. Resistance to the new requirement of
MANDATORY celibacy was rendered powerless by the new political and economic power of the Church."
, but being married to Him means any intercourse with humans would be an extramarital affair and therefore sinful.