1 adverbs to describe how to rigueur

The eldest son is "my lord," and his sisters are "my lady;" and ever since the days of Mr. Foker, Senior, it has been de rigueur for an opulent brewer to marry an earl's daughter; but the younger sons are not distinguishable from the ignominious progeny of viscounts and barons.

1 adverbs to describe how to  rigueur  - Adverbs for  rigueur