The Courts of the Morning by John Buchan

When Archie and Janet came down to dinner that evening at Veiro they found Don Luis de Marzaniga, a little thinner and browner than before, but spruce and composed as if he were about to dine at his Olifa club. He kissed Janet's hand, and asked Archie if he had enjoyed the weeks since his return from the Gran Seco.

"I've been obeying orders," was the answer. "There's my commander-in-chief. She'll tell you how docile I've been, and how I've never bothered her with questions, though Janet and I are sick with curiosity."