From Ludovico Guicciardini, The Low Countries Seen by an Italian, published 1567:

“The woolens of the country are somewhat coarse, inferior in quality to those of Spain and even more to those of England. One reason for this besides the climate is that the pastures here are so nourishing that the animals grow coats which are too think, long and rough.” The Low Countries in Early Modern Times: a Documentary History, p 6.

Ludovico contradicts himself in a later paragraph (reproduced below) stating that wool cloth produced in Holland is of high quality. This could be a result of two things: 1. Wool, i.e spun wool from the sheep’s back, may have been of poor quality, which is why it was imported from other regions. 2. Ludovico is a Florentine, well known for their wool trade, and so may be displaying some form of wool “snobbery” in judging that Holland’s wool is inferior because is not Florentine wool.

“The country produces such large quantities of madder, which here is called garance, that not only do they supply their own country but a large part of Europe as well. They also prodce excellent woad, although in small amounts, and flax and hemp in great abundance.” The Low Countries in Early Modern Times: a Documentary History, p 5.

“Flax does not grow in this country [Holland] and yet it produces more fine linen than any other region in the world, since it obtains flax from Flanders and a certain quantity from Leige and the Baltic, although this flax is not as fine. Holland does not produce wool and yet an enormous amount of woolen cloth, especially for ornamental purposes, is woven here from wool which it gets from England, Scotland and Spain and a little from Brabant.” The Low Countries in Early Modern Times: a Documentary History, p 9.

References

L. Guicciardini, The Low Countries Seen by an Italian from Rowen, Herbert H. “The Low Countries in Early Modern Times: a Documentary History”, Harper and Row, New York, 1972, 06-139310-x