Critical questions for history of science buffs

Clearly, there was no Nobel Prize or any other now globally fairly well'-known international awards in the ancient world. So, what motivated scientists and technologists at that time to think and do great stuff ? What drove ancient Arabs and also Indians to study the stars  ? Issac Newton ( 1642-1727 ) died before Nobel was born. Was - or was not - Newton a great scientist  ? What led him to learn science  ?  Why did Nobel ( 1833-1896 ) himself not choose to be a lawyer or theologian ?