Medieval Globalsim: One of my favorite interests - intellectual contributions (~711-1492) to western civilization.
A short paper about the development of the Heliocentric model for our solar system that connects the dots to show how Copernicus likely knew of the work of Tulsi, a Persian astronomer. Consider this was in the days before the printing press so knowledge was hard won in some cases and a matter of cordial relationships between and among trusted people - "classified information" in some cases, to avoid being labeled a "heretic" by the church.
"Quite a while ago I noticed that "the Tusi couple" is mentioned also in a Hebrew medieval treatise מישר עקוב Meyasher ʿaqov (Rectifying the Curved) by a Spanish Jewish author named Abner of Burgos (c. 1270–1340), also known as Alfonso de Valladolid"