After the death of Shah Ismail in 1522 AD(930 HG), his oldest son Saam Mirza became king. He called himself Shah Tahmasp. Shah Tahmasp lacked his fathers abilities to conquer and organize new territories. Althought he reigned for over 50 years, he was not very important in Irans history. He was a lazy and irrisponsible king, and he loved wine and women more than military life. on the other hand, his reign brought stability ti the country, and because of length of his reign, he established the dynasty of Safavids in Iran.
During the fifty years of Tahmasps rule over Iran, there were several more attacks from Uzbeks and Ottomans on Iran. In one of these attacks, Uzbeks captured a karavan of Royal family and threatened to kill the whole family, but they were defeated by a small army of Ghezelbash soldiers.
The most important chapter of Tahmasp's reign began when his oldest son, Ismail, was accused of conspiracy. Tahmasp imprisoned Ismail in Ghahghahe fort and kept him there for over 10 years. During his time in jail, Ismail, who was very much like his name sake grandfather, found himself a strong army of supporters who were tired of Tahmasp's slow and un-eventful reign. in 1575, Tahmasp escaped from the prison and went to the western Iran (around Kurdestan). He was palnning and attack on Ghazvin(the capital) when he heard the news of his father's death, so he went to Ghazvin to capture the throne.