Complex sentence: In 1939, John Bagot Glubb, better known as Glubb Pasha, became the Legion's commander along with Major General Abdul Qadir Pasha Al Jundi as his deputy commander both transformed it into the best-trained Arab army.
Split into simpler sentences: In 1939, John Bagot Glubb, better known as "Glubb Pasha", became the Legion's commander, with Major General Abdul Qadir Pasha Al Jundi as his deputy commander. Together they transformed it into the best-trained Arab army.