On September 25, 1969, appellant, a Swiss corporation, filed this private antitrust action in the District Court, naming six foreign and domestic corporations as defendants. Two of these corporations were served with the complaint at that time. 1 The remaining four, appel-lees herein, were not served until December of 1973, over four years later. Upon return and pursuant to Fed.R. Civ.P. 41(b), appellees moved for an order dismissing the case as to them for failure to prosecute, which was in due time granted in an opinion filed February 27, 1974. We affirm.

Rule 41(b) provides that: “For failure of the plaintiff to prosecute * * * a defendant may move for dismissal of an action * * * against him.” In Messenger v. United States, 231 F.2d 328 (2d Cir. 1956), this Circuit applied the rule in circumstances similar to those in the instant case and concluded that an unexplained and unreasonable delay in service constituted grounds for dismissal, without regard to any showing of actual prejudice. In granting the motions, the District Court found that appellant had “produced not the slightest rational excuse” for its procrastination and held that Messenger controlled.

Dismissals under Rule 41(b) are, of course, largely a matter of the trial court’s discretion. See Link v. Wabash Railroad Co., 370 U.S. 626, 633, 82 S.Ct. 1386, 8 L.Ed.2d 734 (1962); Taub v. Hale, 355 F.2d 201, 202 (2d Cir.), cert. *816 den., 384 U.S. 1007, 86 S.Ct. 1924, 16 L.Ed.2d 148 (1966). Here, we perceive no abuse of discretion. Messenger is the governing law and the judgments are therefore affirmed. 2