Why did many medieval maps put east at the top?

In medieval cartography, the practice of placing east at the top of a map was common, which is where the term "orientation" originates.1

This convention was often used in schematic world maps, such as the T and O renderings. During this period, mapmakers were frequently influenced by ecclesiastical dogmas and interpretations of Scripture, which shaped how they depicted the world. While later medieval mapmakers were aware that the Earth was spherical, these maps remained largely symbolic rather than strictly navigational tools.1

It was only with the later adoption of the magnetic compass and the development of portolan charts that mapmaking shifted toward the greater accuracy and reliability required for direct navigation.1