When did the Roman's centralized administration fall apart? What took place afterwards and what were the implications? Who kept scientific cartography alive during this time? Who was one of the most famous?

The Roman Empire fell apart in 476 AD, marking the end of the city-state's centralized administration. Afterwards, political power was increasingly decentralized, as small warring states competed to fill the power vacuum left by the fall of Rome. These states inhibited the progress of science and learning, as the absence of a central governing cause led to local warlords competing for resources and power. During this time, Islamic scholars kept scientific cartography alive. Perhaps the most famous was al-Idrisi, an Islamic cartographer who was tutored by the royal court of King Roger II of Sicily from 1139 to 1154. He created the Tabula Rogeriana, the most accurate world map at the time, detailing the geography of the world from Europe and North Africa all the way to Chinese Turkestan. He was a prolific author and cartographer who used mathematical geodesy to map the world in great detail, helping preserve the knowledge of the classical era during the dark ages.