Exceptions to this claimed general rule were the Lancastrian looting of Ludlow after the largely bloodless Yorkist defeat at Ludford Bridge in 1459, and the widespread pillaging carried out by Queen Margaret's unpaid army as it advanced south in early 1461. Both events inspired widespread opposition to the Queen, and support for the Yorkists. Many areas did little or nothing to change their city defences, perhaps an indication that they were left untouched by the wars. City walls were either left in their ruinous state or only partially rebuilt. In the case of London, the city was able to avoid being devastated by convincing the York and Lancaster armies to stay out after the inability to recreate the defensive city walls. Few noble houses were extinguished during the wars; in the period from 1425 to 1449, before the outbreak of the wars, there were as many extinctions of noble lines from natural causes  as occurred during the fighting  from 1450 to 1474. The most ambitious nobles died and by the later period of the wars, fewer nobles were prepared to risk their lives and titles in an uncertain struggle. The kings of France and Scotland and the dukes of Burgundy played the two factions off against each other, pledging military and financial aid and offering asylum to defeated nobles and pretenders, to prevent a strong and unified England from making war on them.. In a period of how many years before the outbreak of the wars were there as many extinctions of noble lines from natural causes as occurred during the fighting?