The era of the Sahaba ended at the last decade of this century and was followed by era of their followers, the Tabi'in. The scholars among them became responsible for Fiqh and giving Fatwas1.
In the main cities, this are the death date of the last Sahaba:
^ There are different opinions on the date. al-Waqidi and Ibn Sa'd, author of Tabaqat Al-Kubra, put the date as 12th Rabi ul-Awwal, and this generally accepted.