Isaac Barrow was one of the professors who taught Isaac Newton at Cambridge. According to this page, he is said to have made contributions to the Fundamental Theorem of Calculus that was devised by Newton.
What specific contributions did Barrow make to this theorem? What formulae, conjectures, or hypotheses did Barrow develop that assisted in the formulation of the theorem?
If there are any articles or citations that document Barrow's contributions, please post an answer with the appropriate links below. Thank you in advance!