Al-Imaam Abu Daawud, Sulaiman bn al-Ash'ath, was a scholar in Baghdad before the ruler sent him to Basrah to enliven the city after it had been ravaged by war.
The ruler, who personally came and met Abu Daawud in the masjid after Maghrib, said: 'Please you will have to move to Basrah and take it as an abode, then students of knowledge will seek you there and the city would come alive again, because it has become desolate, and people had broken away from it because of the tribulation of az-Zinj (a rebel).'
Al-Ahmad Abu Daawud accepted the request. There were two others, he partially accepted the second one while he rejected the third one outright.
That was how Abu Daawud became the Scholar of Hadeeth of Basrah.
May Allaah bestow mercy on him.