I've observed over many occasions of looking up etymologies for words that so many words that entered English during the Middle English and Early Modern period (I don't know the figures) were of Middle Dutch origin, according to linguists. This really surprised me, as besides trade links, I don't know of any particularly close social, cultural, or political ties of England to the Low Countries until the late 17th century. And so many of these words are common, everyday words. (Again, I can't name any off-hand, but perhaps someone could contribute a few.)
So, what could be the reason for this large of influx of common words from Middle Dutch? My gut reaction was that perhaps the etymologists just got it wrong in some of these cases, since with English and Dutch both being Low German languages (within the West Germanic Branch), there's a chance a certain word went completely unattested in surviving texts until relatively late.
Examples of such words: wagon, blare, bicker, blink, block, blow, deck, golf, grab, hoist, leak, pickle, plug, morass, pit, pump, smelt, slim, slurp, snack, split, stern, trigger