From October 1978: The first combined issue of 2000AD AND STARLORD.
Most mergers tended to be half-hearted affairs with incoming strips shoehorned into the existing title (and foisted on an editorial team who had no part in their creation or interest in their long-term success) at the behest of the circulation department in the hopes that some of the readers of the just-defunct book would switch sides and start reading the victorious weekly.
This tie-up, it has to be said, is probably one of the most successful in the STARLOGGED era. Not only did it give Tharg a stonking line-up of strips but the arrival of Strontium Dog and Ro-Busters transferred two strips that would become synonymous with the galaxy's greatest.
I've seen some reports that suggest that STAR LORD was still actually outselling Tharg when the decision was made to close it. The logic being that its sales were dropping faster - and it was a more pricy proposition - so the older of the two weeklies was deemed to have the best long-term chances of survival. At least that turned out to be right.
Tharg didn't make a habit of providing sanctury to his fallen colleagues. After the less successful merger of TORNADO, the alien editor put a stop to all future shotgun weddings and - after a bedding-in period - the EAGLE became IPC/ Fleetway's main vehicle for mergers as the the number of victims really started to pile up.