An antrustion (Latin: antrustio, plural antrustiones) was a member of the bodyguard or military household of the Merovingian kings of the Franks.
[1] An alternative etymology relates it to proto-Germanic *druhtiz, warband, whence old high German truht and perhaps Slavonic druzhina.
[4] Anyone desiring to enter the antrustions had to present himself armed at the royal palace, and there, with his hands in those of the king, take a special oath or trustis and fidelitas, in addition to the oath of fidelity sworn by every subject at the king's accession.
The antrustion was always of Frankish descent, and only in certain exceptional cases were Gallo-Romans admitted into the group.
For each expedition, the king raised an army of citizens in which the Gallo-Romans mingled more and more with the Franks; they only kept one small permanent body which acted as their bodyguard (trustis dominica).