At what point did we stop stealing/erasing/rewriting the findings of others and begin a collective planetary history? I was studying astronomical distances and saw scientists like Kepler and Newton used measurements from the Greeks. I would like to know when this change occurred and how socially evolved we were.
Interest in other cultures is not exactly knew. One of the best known cases in the Middle Ages (just to mention a period of time falsely considered to be bad for progress) is that of the House of Wisdom in Baghdad.
Specially under the Abbasid caliph Al-Mamun, translations from other languages into Arabic were encouraged. Works by Classic authors such as Hippocrates, Euclid and Galen, but also from India too, like the astronomical tables of Sindhind.
With that combination of available translations and tolerance for other cultures and religions (for example, Hunayn ibn Ishaq, one of the most famous translators, was Nestorian), scholars of the caliphate were able to produce very important works on maths, astronomy, medicine, etc., which later spread to other countries. A good example of that is the origin of our words for 'algebra' (from The Compendious Book on Calculation by Completion and Balancing by Al-Khwarizmi) and 'algorithm/algorism' (from Al-Khwarizmi's very name).
If you want to know more, a nice introduction might be The House of Wisdom: How the Arabs Transformed Western Civilization, by Jonathan Lyons.