Allah the Exalted has conferred a special blessing upon this ummah - that is, the whole earth has been declared a mosque for it. Therefore, when the time for prayer comes, a Muslim may pray wherever he may be

The excellence of building mosques:
'Uthman reports that the Prophet sallallahu alehi wasallam said: "Whoever builds for Allah a mosque, seeking by it Allah's grace, Allah will build for him a house in paradise." This is related by al-Bukhari and Muslim. (Leran More about Masjids in Fiqh Al-Sunnah )

Ibn 'Abbas reports that the Prophet sallallahu alehi wasallam said: "Whoever builds for Allah a mosque, even if it be tiny, like a bird's nest, Allah will build for him a house in paradise." This is related by Ahmad, Ibn Hibban, and al-Bazzar with a sahih chain.

Due to these Hadiths , Muslim expand in building mosque , These mosque are inhabited by ascetics , Sufisim ,mentioning God very much , believers in God , by studying symposiums of  jurisprudence, logic and modish, literature, councils of criticism , eloquence, grammar and meeting symposiums that tackle all sciences .

   Mosques are religion, morality, light , hermitage for the monk , also it is a school for student .

  If we added to all the above mentioned that hand of reform and repairmen wasn't hesitating in repairing any crack that appears in the ancient mosques , we would have realize the importance the Islamic architecture enjoyed and if this how architecture in the whole Islamic world.

Normally, the Mosque's architecture didn't remain as it was in the age of the prophet and the orthodox caliphs , yet it began developing in order to cope with the Islamic civilization , as the "Omawian" state saw that its buildings especially the religious ones should not be less in value and evaluation then the jewish and Christian temples in Egypt and in east Asia countries.

   Hence the "Omawian" Mosque was built with a different technique and method then the first Mosques, and this was a necessity for the new state's circumstances, Nations of civilization and the advanced formative arts which came into Islam and became important elements in the Islamic empire.  

   Thus, the Mosque's function wasn't limited in the Islamic new community  as performing prayers only but it was performing many other functions which are the most important of which was the cultural aspect, as in its propylaeum and around its pillars- study symposiums, guidance- were multiplied.

     Also, sessions were held in it to solve the civil and religious conflicts.There was also "house of money " as it was in the "Omawain"Mosque and in "Amr's" Mosque in which " Metwali El- Hesba" was sitting.   

    Out of this, we conclude that Mosques in the "Omawain "  and in the beginning of the "Abassian" age in less estimation , were representing the  government's role in our modern concept in addition to its religious   as a main function and its normal as the Mosque became performing services and other many functions  that differ with Nations' and communities' difference - that the constructive methods multiple in building Mosques even that it all took components of the Islamic architecture and its substance , as most Mosques till the 4th Hijra century were containing an uncovered plat surrounded by propylaeums from (3) fronts or (2) on the condition that the biggest large sitting room must be "Kibla" for its importance , and each Mosque contained one prayer niche or more , pulpit and minarets.    

   The Mosque's design was mostly squared in Iraq and Iran , rectangular in Egypt ,East Asia countries and North Africa , the explanation is easy, as in the adoration places before Islam in countries between the two Rivers were of a squared construction, we mean (Atsh Gah) i.e house of fire, while in West of the Islamic world where  Christianity prevailed their churches were mostly of rectangular construction.      

    In the second half of 14th Hijra century new names for adoration places stated to appear in eastern the Islamic world that were known by schools , then it were deployed in western the Islamic world in 5th Hijra century and this change in names had to be for a wisdom stated by the new function or the direct motive.