在基督教里，认为耶稣的本性仍和神性在一起而非人性，即使他已经在人间实现了人的生死轮回。一性论学说宣称，在耶稣基督人的里面只有里一个神性而非两个，即神性和人性，正如451年卡尔西顿宗教会议上所宣称的一样。在4、5和6世纪里基督人性的学说的发展里面，一些有分歧的传统逐渐出现。卡尔西顿会议通过了这样一个法令，即“基督已经确认两由性，没有被混合、改变或者是分离。”这个陈述在一定程度上是与诺斯替说学相对的——基督身上的两性仍然是分离的，并且它们是发挥作用的两个人——一定程度上反对理论上的修道士优提克斯单纯的位置，在448年优提克斯因为教授下列理论而遭到谴责，即在道成肉身之后，基督只有一性，并且肉身的基督的人性和其他人所构成的物质不同。政治和教会的对抗和理论一样在卡尔西顿驱逐并开除Dioscorus的决定中起到了重要的作用。支持Dioscyus并坚持他的教导与亚历山大里亚的圣•西里尔的正统学说是一致的教派被贴上了一性论派的标签。
这个标签也同形形色色的理论家和群体相联系，虽然他们中有些被称为一性论者，如著名的安条克的塞维鲁，就拒绝自身就自相矛盾的卡尔西顿用语。大部分的现代学者同意塞维鲁同Dioscrus一样，可能反对在他们对在基督那里上帝和人的团体的亲密关系多于在任何基督人性和人类是同质的拒绝中被界定为正统的理论。
在近代，通常被界定为一性论派的这些教会（亚美尼亚使徒派，埃及正统基督派，埃塞俄比亚正统派，叙利亚正统派）作为在耶稣基督人的学说上的本质的正统，基本已经被罗马天主教、东正教和新教国家所接受。
in Christianity, one who believed that Jesus Christ's nature remains altogether divine and not human even though he has taken on an earthly and human body with its cycle of birth, life, and death. Monophysite doctrine thus asserted that in the Person of Jesus Christ there was only one (divine) nature rather than two natures, divine and human, as asserted at the Council of Chalcedon in 451. In the development of the doctrine of the Person of Christ during the 4th, 5th, and 6th centuries, several divergent traditions had arisen. Chalcedon adopted a decree declaring that Christ was to be “acknowledged in two natures, without being mixed, transmuted, divided, or separated.” This formulation was directed in part against the Nestorian doctrine—that the two natures in Christ had remained separate and that they were in effect two Persons—and in part against the theologically unsophisticated position of the monk Eutyches, who had been condemned in 448 for teaching that, after the Incarnation, Christ had only one nature and that, therefore, the humanity of the incarnate Christ was not of the same substance as that of other men. Political and ecclesiastical rivalries as well as theology played a role in the decision of Chalcedon to depose and excommunicate the patriarch of Alexandria, Dioscorus (d. 454). The church that supported Dioscorus and insisted that his teaching was consistent with the orthodox doctrine of St. Cyril of Alexandria was labeled monophysite.
The label also was attached to various theologians and groups, although some who were called monophyste, notably Severus of Antioch (d. 538), repudiated the terminology of Chalcedon as self-contradictory. Most modern scholars agree that Severus as well as Dioscorus probably diverged from what was defined as orthodoxy more in their emphasis upon the intimacy of the union between God and man in Christ than in any denial that the humanity of Christ and that of mankind are consubstantial.
In modern times, those churches usually classified as monophysite (the Armenian Apostolic, Coptic Orthodox, Ethiopian Orthodox, and Syrian Orthodox) are generally accepted by Roman Catholic, Eastern Orthodox, and Protestant Christendom as essentially orthodox in their doctrine of the Person of Jesus Christ.
