The human being ceases to be central part of Art in Europe with the arrival of the Dark Ages, only to return with the Renaissance.
What are some factors that explain that?
The Dark Ages was a period in which all of society revolved around self-contained agriculture, with the land being owned by the three upper classes (the nobility, the clergy, and, so to speak, the "Crown"). It was based upon a very strict hierarchy, with mobility reduced to a minimum. Those at the top could not maintain this de facto state without an ideology, the effect of which is lending legitimacy. This ideology consisted mainly of the notion that they, personally, were ordained by Heaven to rule mankind. This notion was the only thing they lacked - the other, the monopoly on the use of violence, they already possessed, given that they formed a class of professional warriors, and could very simply crush a peasant rebellion. The idea that God worked only for a few handful of men turned Him away from the larger part of society, losing thus connection with the bulk of mankind. Thus, in my opinion, anthropocentrism disappears in the Dark Ages, only to resurface in the Late Middle Ages, when, not coincidentally, town life flourished and the old patriarchal order was seriously challenged. I don't think, however, that anthropocentrism is a good denomination, because it was not so much a question of man slipping in the background, as that of the masses doing so. It was not so much a question of God becoming paramount, as that of Him becoming so for a select few.
L.E. At the heart of the matter lies the fact that Art, however much we like to agree or not, was, back then, the reflection of the mentality of the powerful. Given the fact that Power was profoundly personal in nature in those times, it could not have been helped that Art itself was reflecting this pathologically elitist view of the Universe. The notion of ruler responsibility, which meant, to a certain degree, an equivalence between ruler and masses, necessarily disappeared with the dissolution of the Roman State. With it also disappeared any hope of artistic workings concerning mankind at large.
L.E.2 I was just reading this morning some of Rostovtzeffs history of Rome, and the following fragment caught my attention, in view of the topic of this thread:
He is speaking of Diocletian, under the rule of which Western Europe made some of the most important steps towards the Dark Ages. Notice how when Power is estranged from the masses, when it can no longer strengthen its claim through democratic arguments, it drifts, not accidentally, towards the higher fora of the world - God and the Heavens. It seeks to form and ideological alliance with supernatural elements. This is inherent, I think, to all private systems of power.
Due to the backwardness of the economy, human life was very precarious and uncertain, which encouraged people turning towards God. The threat of starvation constantly loomed over the realm. A slump in agricultural productivity occurred at the onset of the Dark Ages:
And lasted till around 1000 A.D.:
The fall of the Roman Empire coincided with a "cold and wet pulsation of the climate", a macrohistorical phenomenon which, as mentioned above, sinks agricultural productivity and encourages pestilence. War raged on forever, it's major effect being the destruction not only of labor, but also of capital, which is significant. Moving armies were also the major agent of epidemics, due to their appalling sanitary conditions. Internal wars were coupled with external invasions (Huns, Saracens, Hungarians, Normans, Vikings etc.) Physicians were either completely absent or completely impotent before most of diseases. The lack of concentrated accumulation of capital, which is a result of agrarian, atomised economies, meant impossibility of investing in large-scale, welfare projects. The Church, it is true, was the main purveyor of such activity, but it could not have done more than the Age permitted it. Scientific solutions were also lacking, mainly because, in the lack of economic stimuli, science, even if latent, can't evolve, can't be brought to concrete fruition.
The lack of science automatically means turning to supernatural explanations when trying to understand natural phenomena. Casual relationships and logical reasoning are abandoned leading to a embracing of mysticism. This meant, on the one hand, constantly appealing to God, on the other hand, a belittling of oneself and of oneselfs capacity to penetrate the mysteries of Nature. As I said before, scientific breakthrough is not necessarily the result of intellectual prowess, as the result of adequate economic support. The collapse of the Roman Empire, it is well known, meant a drastic reduction in the extent of the market, which further diminishes the division of labor, without which advanced technologies and know-how's are lost.
"Anthropocentrism" is a bit more than portraying humans in art: it's considering humans central to Life and Universe, to the point of believing that Universe was created with humans in mind. From that point of view Medieval times were pretty much anthropocentric, with Earth located in the centre of the Universe that was created by a human-looking God that cared so much about the actions of representative of human species, which were distinctly higher than other species.
Simple answer is that the Church was the dominant power during Medieval Times and the focal point of life. The Church emphasized the after-life and to some extent demeaned/trivialized earthly existence - it was simply a transitory phase - a means of gaining the after-life. Therefore making Earthly Man the focal point of art was not reflective of the spirit of the times.
In ancient times, and again during the Renaissance and into modern times, various forms of secular humanism prevailed - Man on Earth was the focal point of existence and the art of the times reflected that.