old money

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The inherited wealth of established upper-class families.
• noun A person, family, or lineage possessing inherited wealth.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun idiomatic Families that have been wealthy for generations or members of such families.
• noun UK The monetary system used in the United Kingdom before decimalisation (1971) and consisting of pounds, shillings, pence and farthings.
• noun humorous The imperial system of measurement, as opposed to the metric system.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the inherited wealth of established upper-class families