Both r datta avataars altough both were conteporaries. swami samartha was none other than sri nrisimha saraswati of gangapur( 2nd avataar of sri datta in this age of kali) who dissappeared in the kadali vana, srisailam to reppear @ akkalkot as sri swami samarth. @ the time of his mahasamadhi he told one of his ardent devotees who could not bear his separation that he can hence forth find his other form in shirdi as sri sai samarth. later when this very bhaktha went to shirdi sri sai samarth confirmed this statement. datta bhaktas believe the following as his avattars in kali yuga 1. sri sripada srivallabha ( pithapur, kuruva puram), sri nrisima saraswati , ganga pur, sri manikya prabhu , manikya nagar humnabad, sri swami samrtha , akkalkot, sri sai samarth , shirdi.