The notion that the earth was flat was the position of religionists. And like the ignorant/illiterate 'earth is flat' people of centuries ago, YOU keep repeating nonsense that has been totally refuted.
The myth that Christians in the Middle Ages thought the world was flat was given a massive boost by Andrew Dickson White's weighty tome The Warfare of Science with Theology. This book has become something of a running joke among historians of science and it is dutifully mentioned as a prime example of misinformation in the preface of most modern works on science and religion. The flat Earth is discussed in chapter 2 and one can almost sense White's confusion that hardly any of the sources support his hypothesis that Christians widely believed in it. He finds himself grudgingly admitting that Clement, Origen, Ambrose, Augustine, Isodore, Albertus Magnus and Aquinas all accepted the Earth was a globe - in other words none of the great doctors of the church had considered the matter in doubt. Although an analysis of what White actually says suggests he was aware that the flat Earth was largely a myth, he certainly gives an impression of ignorant Christians suppressing rational knowledge of its real shape.
"The long association between Christianity and the flat-earth theory begins in the sixth century when a Greek monk of Alexandria, Cosmas, who had traveled widely in the East, retired to a cloister in Sinai and wrote his Christian Topography. In it he refuted the 'false and heathen' notion that the earth is a sphere, and showed that it is really a rectangular plane arched over by the firmament which separates us from heaven. The inhabited earth, with Jerusalem at its hub, is at the centre of the plane, and it is surrounded by oceans beyond which lies Adam's paradise. The sun revolves round a north polar mountain, circling its peak in summer and its base in winter. Christian Topography was well received by the Church, whose policy at the time was to eradicate all previous knowledge and establish itself as the sole authority in religion, philosophy and science. The flat-earth theory, hitched on to the geocentric cosmology of Ptolemy, prevailed among clergymen (if not among navigators) until the sixteenth century, when Copernicus called it into question by venturing the idea that the earth is a planet orbiting the sun. He was not very assertive. The preface to his book emphasized that the heliocentric system was merely a hypothesis, and Copernicus avoided controversy with the reviewers by dying on the day it was published."
I'm glad to learn that, with the help of Copernicus, the Church eventually rejected the flat earth concept.