When Mohammed escaped Medina, the Muslim community had just gotten there and understandably there were no mosques (as they had arrived within weeks). Mohammed, once there, constructed the Masjid an-Nabawi (the Prophet's Mosque) which remains the holiest site in Medina. It is likely that he built a few additional mosques as more people converted, but there are no exact figures.
The best estimate would be between 1-5.
Current Medina was called Yathrib during the time of Prophet Muhammad (S).
Abou Bakr was the prophet companion during his migration to Medina (Madinah in Arabic). Abou Bakr was the first Caliph (Muslim State ruler) after prophet Muhammad death in year 632 AD.
~Muhammad was his son-in-law. Abu Bakr was a close companion to Prophet Muhammad (PBUH) and the first man believed in Muhammad prophesy and accepting Islam religion. Abu was the only companion to Prophet Muhammad during his Immigration from Mecca (Makkah) to Medina. Abu Bakr is the father of Aisha, (may God be pleased with her) Prophet Muhammad wife. Abu Bakr was the 1st Caliph (Ruler) after prophet Muhammad death.
On arrival of prophet Muhammad (PBUH) to Medina coming from Makkah (Mecca) during Hijra in year 622 AD.
Prophet Muhammad undertook significant actions during his lifetime, including spreading the message of Islam, establishing the first Islamic community in Medina, leading military campaigns to defend and expand the Muslim community, and setting a moral and ethical example for his followers.
The Prophet (PBUH) went to Madina when the makkans were attempting to kill him, Madina was the first area to accept Islam fully.
The Muslim people made Kubba or Green Kubba for the city of Madina (not Madeena).
Muhammad was buried in his own house, which had already served as a mosque for some years. The mosque still lies there, and is counted as the second most important mosque in Islam, and Madina the second most holy city.
The first mosque of Islam was built at the village of Quba by Prophet Muhammad during the migration to Yathrib ( Madinah )
In Islam, the first mosque was built by Muhammad in Quba, while he was travelling to Medina (Hijra). The first Friday prayer in Islamic history was also offered in this very mosque.
Some major events in Prophet Muhammad's life include receiving the first revelation from God through the Angel Gabriel, migrating from Mecca to Medina (known as the Hijrah), conquering Mecca, and delivering his farewell sermon during his last pilgrimage. These events were pivotal in shaping the development of Islam and the Muslim community.
Salah was made mandatory to Muslims during prophet Muhammad (PBUH) trip to the Heavens that is called the rising up (called in Arabic Al-Mi3raj). This was before prophet Muhammad (PBUH) migration (Hijra in Arabic) to Medina. It is the only Islam pillar that is commanded directly by God and not through the angel Gabriel (Jibril).