Every since Thread first appeared to the colonist of Pern. The fight for survival began. Fifty Turns of falling death ending with a two-hundred Turn period to recover. Only to once more prepare for the fall of Thread. The Dragons were created to fight Thread head on along with their life bond Riders. To rise and meet Thread in the air, letting lose torrents of flame. Turning the silver rain of death into ash. Turns later would greet the unexpected arrival of the Whers, first seen as a failure. Later a boon. For they too could flame and fly, rising to fight Thread in the dead of night. For over 5,000 Turns the clock work cycle continued on. It was during the cycle that Thread did not come as expected, a resting period that lasted four hundred and fifty Turns. The Harpers recorded this odd Interval yet like everything that was perishable. Those hide records were lost by time and neglect. This lack of knowledge would never be able to forewarn the Pernese of another possible oddly long Interval.
Enter the 8th Pass, Turn 2008. Like any other Pass the Pernese were preparing for Thread. The six Weyrs of Pern were full to the max. The flow of clutches, the number of graduating Weyrlings, number in each Wing, the Weyrs were threaten to be overrun. An unanimous agreement was made by the Weyrleaders and other Leaders of Pern to find a new Weyr. Like the lost of the knowledge of an extended Interval, all fears of the South had long been forgotten in turn. Scouts were sent and soon a site for the new Weyr was found. Construction was set and soon Isla was founded.
A few Turns after the founding a group of Wherhandlers wished to claim land in the South. The land was granted as Whers were valued as much as Dragons. Having help destroy Thread that fell at night. Close to the new Weyr the first Wherhold was established and as the Pass entered the next Interval Holds were settled, even Halls. The success of the first Wherhold opened the way for a second. Pern was once again settling into the cycle of living, the Weyrs training new Dragonriders, the Wherholds training new Wherhandlers.
Enter the 8th Interval, the second time Pern would witness a four hundred and fifty Turns of time of peace from Thread. The second time Pern would enter the extended Interval without any foreknowledge. When Thread was due and did not Fall, Pern was at a lost. Then as the fifty scheduled Turns came and went with still no Thread. Pern began to believe Thread was gone forever. Thread began to turn into a myth, and the number of Dragons and Whers slowly declined over the Turns. The Weyrs and the Wherholds taking on secondary jobs to support themselves and keep the Lord Holders happy enough to continue sending tithes. Scouts, hunters, farriers, scouts, guards, messengers, all of which were suitable to those bonded to Dragons or Whers. Duties that spared the Holds from sending needed hands from the Hold or fields. Allowed shipments to arrive on time, and more. Four hundred and fifty Turns of this peace and Pern was forgetting. Weyrs were not teaching their Weyrlings to train for Thread. The Lord Holders were not keeping an eye on their fields and forests. All but Isla and Calhoun. They have never lost faith in why they were needed, though they too took on these secondary jobs they still trained their Weyrlings for Thread. For they were sure Thread would return.