The Power Of Beer

From The Confident Hope of a Miracle, Neil Hanson's book about the Spanish Armada:

The shortage of beer was a potentially crucial issue; British soldiers and sailors had refused to fight in the past when supplies ran low. An expeditionary force of 7,000 soldiers sent to Spain by Henry VIII mutinied when they found that beer was unobtainable there, and in invasion of Scotland in 1542 was twice postponed because the beer ships had not arrived from London. When they finally did, they brought only enough to sustain a four-day campaign. Despite meeting no resistance from the Scots, the English troops retreated as soon as the beer ran out. The Scots mistook the cause of the retreat, launched a premature invasion and were then slaughtered on Solway Moss.