Palcom was started up in Europe as a subsidiary of Konami during the NES era.
This was because Nintendo had a very strict publishing policy for third parties, only letting them publish up to 5 games per year. Since Konami had lots of games out in Japan that they wanted to localize, they started up this division so they could release the games under that name.
There was a similar situation in the US with the Ultra Games subsidiary of Konami.
Both subsidiaries published pretty much the same games, but Palcom actually did publish a few games that Ultra Games did not, such as Parodius and Pop'n Twinbee.