Complex sentence: The most enduring Mamluk realm was the knightly military caste in Egypt in the Middle Ages that rose from the ranks of slave soldiers who were mainly Turkic peoples,, Egyptian Muslim soldiers, Egyptian Copts, Thomas Philipp & Ulrich Haarmann.
Split into simpler sentences: The most enduring Mamluk realm was the knightly military caste in Egypt in the Middle Ages, which developed from the ranks of slave soldiers. These were mostly enslaved Turkic peoples,, Egyptian Muslim soldiers, Egyptian Copts, Thomas Philipp & Ulrich Haarmann.