Complex sentence: With knives held to their throats, the Jewish patriarchs were forced to vocally proclaim their "allegiance" to Islam as it was agreed upon by the leaders of the community that in order to save the remaining 2,400 Jews, everyone must convert.
Split into simpler sentences: With knives held to their throats, the Jewish patriarchs were forced to vocally proclaim their "allegiance" to Islam. It was agreed upon by the leaders of the community that in order to save the remaining 2,400 Jews, everyone must convert.