In 1958 the party merged with the Yoruba-dominated Republican Party of Dahomey (PRD) led by Sourou-Migan Apithy to form the Dahomeyan Progressive Party, which was to be the Dahomeyan branch of the African Regroupment Party.[1] However, internal disagreements led to the parties splitting back into their original forms in 1959.[4] The RDD won 22 seats in the 1959 elections, and in 1960 agreed to merge with the PRD again, this time under the name Dahomeyan Unity Party.[4]