Complex sentence: The regiment had been raised with dubious methods from various nationalities in Albania and the Ottoman empire, and the troops, who had arrived on Malta in 1806, were unhappy with their rank and pay.
Split into simpler sentences: The regiment had been formed using dubious methods, with personnel recruited from various nationalities in Albania and the Ottoman empire. The troops, who had arrived on Malta in 1806, were unhappy with their rank and pay.