An attractive, briskly paced debut novel by the author of nonfiction studies of medieval merchant guilds--on which Lang (in her first US publication) unobtrusively grounds this lively romance, set in 1377. In the days of the waning Edward III, Joanna Burgeys, daughter of a prominent London mercer (dealer in cloth), is rescued from probable street rape by a knight, Sir Tristram de Maudesbury, retainer to the Duke of Lancaster (the later powerful John of Gaunt). Sir Tristram is a mean-spirited, callous--but divinely handsome--rotter, and Joanna is smitten. She uses her decidedly superior wit (eventually) to trick the rather dense Tristram--who, it turns out, wants Joanna's beautiful sister Mariota for marriage (predictably, a nasty surprise). Yet Joanna is determined to love on. (One of the pleasing features of the novel is Lang's stubborn, cross-witted heroine.) Meanwhile, London--always at the boil politically with the infighting of the guilds, incursions of foreign workers, and delicate balancing of alliances attuned to mayor or monarch--has had to deal with the threat of a Lancaster invasion, and then the Wat Tyler rebellion of peasants. In the midst of the city's turmoil, and the ascendancy of that rather awful boy Richard II, the fortunes of the Burgeys family are affected by (among others) Mariota's rich and sneaky husband and the ``Black Nick,'' an extraordinary sea captain who turns out to be a knight and neighbor of Sir Tristram's. There will be sad and horrible deaths, close escapes, and the terror of the rebellion. (Wisely, Lang does not allow her well-to-do principals any egalitarian sympathies, although Black Nick comes close.) And, of course, Joanna--post-stupidity--finds true love. A delightful historical--and Lang has, first off, thoughtfully provided a long list of characters, real and fictional.