Ibn Katheer, At-Tabari, As-Syooti and Other Historians. The four Rightly guided Caliphs (Khaliph’s) Abu Bakr As-Sideeq, Umar ibn Al-Khattaab, Uthmaan Ibn ’Affaan and Ali Ibn Abi Taalib. The Biography of Umar Ibn Abdel-Azeez who is regarded as one of the Rightly Guided Chaliphs is also included in this book.
