
William P. answered 10/10/19
MA in Philosophy, with specialization in Analytic Philosophy
Brentano was clearly an important influence on Husserl and those that followed the school of phenomenology. As you say, there is no clear-cut divide. It looks differently if you subscribe to continental or analytic traditions. From the Analytic tradition, as you mention, Frege is a key figure, as well as the British philosophers (Moore, Russel, Wittgenstein) who established this school of thought.
Analytic philosophy is characterized by: "(i) the recognition that philosophical speculation must be grounded in pre-philosophical thought, and (ii) the success achieved in understanding, and separating one from another, the fundamental methodological notions of logical consequence, logical truth, necessary truth, and apriori truth" (Soames, 2003, xi). Analysis is taking the various philosophically interesting concepts apart and clarifying them. This methodological approach, in my opinion is one of the main points of divergence between continental philosophy and analytic philosophy. It seems to me that the subject matter, philosophically interesting concepts (e.g., freedom, responsibility, knowledge, personal identity etc.), of both schools of thought is the same. The divergence is in method.
I recommend Scott Soames' two-volume series for a clear explanation of the history of analytic philosophy. "Philosophical Analysis in the Twentieth Century: Volume 1: Dawn of Analysis" (2003) and "Philosophical Analysis in the Twentieth Century: Volume 2: the Age of Meaning" (2009)