The Count of Soure title was created by King John IV of Portugal by letters patent of 15 October 1652 in favour of João da Costa.

Holders Representation of the title remained in the legitimate line of succession, but the descendants of Gil Eanes da Costa passed the title on to the Counts of Redondo, as the title had fallen to Maria Luísa da Costa, sister of the 7th Count, Henrique José, and she had married the 7th Count of Redondo.

[3][4] After the establishment of the Republic and the end of the nobiliary system, there were still suitors for the title: