Abu Bakr As-Siddique (Radhi Allahu Anhu - May Allah be Pleased with Him) was the first Caliph of Islam and the ideal Muslim, surpassing all other Companions in all stages of life from the day he embraced Islam until the day he died. During the Prophet's lifetime, Abu Bakr was an exemplary soldier on the battlefield; after the Prophet's death, Abu Bakr (ALLAH Bless With Him) remained steadfast and, through the help of Allah, held this nation together. When suggestions of keeping the Usaamah's army back were made by others, Abu Bakr insisted - and correctly so - that the army should go on with the mission which the Prophet (S) had in mind. When people refused to pay Zakaat, Abu Bakr was the one who remained firm and took decisive action when the apostates threatened the stability of the Muslim nation. These are some of the examples of Abu Bakr's many magnificent achievements throughout his life. I have endeavored to describe all of the above in a clear and organized manner and tried to show how Abu Bakr's methodology as a Muslim and as a ruler helped establish the foundations of a strong, stable, and prosperous country - one that began in Al-Madinah, which was been extended throughout the Arabian Peninsula, and then reached far-off lands outside of Arabia.
Abu Bakr As-Siddiq (ALLAH Bless With Him) faced both internal and external challenges throughout the brief period of caliphate of Abu Bakr (about 2 years); the former mainly involved quelling the apostate factions of Arabia and establishing justice and peace among the citizens of the Muslim nation; and the latter mainly involved expanding the borders of the Muslim nation by spreading the message of Islam to foreign nations and conquering those nations that stood in the way of the propagation of Islam.
Khalifah Abu Bakr As Siddeeq (ALLAH Bless With Him) sent out armies that achieved important conquests during the era of his caliphate; for example, Muslim army gained an important victory in Iraq under the command of Khaalid ibn Al-Waleed (ALLAH Bless With Him). Also, the Muslim army achieved other important victories under the commands of Al-Muthannah ibn Haarithah (ALLAH Bless With Him) and Al-Qa'qaa ibn 'Amr (ALLAH Bless With Him). In short, the victories achieved during the era of Abu Bakr's Caliphate paved the way for victories that later took place after Abu Bakr's death. I have tried to evaluate the above-mentioned conquests and to break down the reasons why they were such monumental successes. I particularly pointed out Abu Bakr's contributions to those conquests: His military strategy, the leaders he chose, the letters through which he communicated with them, and so on.