A colleague is looking at migrating some DTD-compliant EAD finding
aids to be schema-compliant, and the @mainagencycode  within the eadid
is set to not have a country code prefix. As far as I can tell, the
@mainagencycode values within schema-compliant EAD are constrained to
ISO 15511 values *with* country codes, but this constraint is not
there for DTD-compliant EAD.

I'd like to verify this is correct, as the tag library for EAD 2002
<> specifies the following:

MAINAGENCYCODE -- A code in <eadid> compliant with ISO/DIS 15511
Information and Documentation International Standard Identifier for
Libraries and Related Organizations (ISIL). Values should be supplied
without the country code, which should be placed instead in the
COUNTRYCODE attribute.

However, my colleague is unable to get @mainagencycode values without
the country code prefix to validate, leading the validation engine to
state that codes such as "US-CtY" are invalid.

Mark A. Matienzo
Digital Archivist, Manuscripts and Archives
Yale University Library