Complex sentence: Leopold Löw, who increasingly became more independent, slid toward Geiger's ideology and even boycotted the Congress and demonstrated sympathy for the Orthodox, became estranged from the lay establishment of the Bureau.
Split into simpler sentences: Leopold Löw, who increasingly became more independent, slid toward Geiger's ideology and even boycotted the Congress, demonstrating sympathy for the Orthodox. Löw became estranged from the lay establishment of the Bureau.