The Morthanveld and the Culture maintained good relations with each other from the time of contact and into the 2nd millennium CE. The two shared similar points of view but were not allies. The Morthanveld were wary of Special Circumstances (SC), and Culture policy at the end of the 2nd millennium CE was to "disarm" SC agents being sent into Morthanveld as a matter of courtesy.
Contact was established with the Culture thousands of years before the Idiran-Culture War. The Morthanveld were neutral during the war. The Morthanveld and Culture were at technological parity at the start of the 2nd millennium CE; at the time some Culture Minds believed the Morthanveld were on the brink of becoming like the Culture.