Complex sentence: Having settled matters in Khurasan, Harun returned to the west in November 805 and prepared a huge retaliatory expedition for 806, with troops from Syria, Palestine, Persia, and Egypt, according to al-Tabari numbering 135,000 regular troops and additional volunteers and freebooters.
Split into simpler sentences: Having settled matters in Khurasan, Harun returned to the west in November 805 and prepared a huge retaliatory expedition for 806, drawing men from Syria, Palestine, Persia, and Egypt. According to al-Tabari, his army numbered 135,000 regular troops and additional volunteers and freebooters.