Complex sentence: The term also applied as the rank title of the field officer that was in charge of a captaincy (group of companies) of the "Ordenanças", the Portuguese territorial militia that existed from the 16th to the 19th centuries.
Split into simpler sentences: The term also applied as the rank title of the field officer that was in charge of a captaincy (group of companies) of the "Ordenanças". The "Ordenanças" being the Portuguese territorial militia that existed from the 16th to the 19th centuries.