Complex sentence: Before Leo Baeck College was founded there was no institution for training Reform rabbis in Britain and all ministers had either received their training in the United States or had been graduates of the Orthodox Jews' College who had later switched allegiance and served Reform synagogues.
Split into simpler sentences: Before Leo Baeck College was founded there was no institution for training Reform rabbis in Britain. All ministers had either received their training in the United States or were graduates of the Orthodox Jews' College who had later switched allegiance and served Reform synagogues.