Sentence:  Soo within a whyle kynge Pellinore cam with a grete hoost / and salewed the peple and the kyng / and ther was grete ioye made on euery syde / Thenne the kyng <WSD>lete</WSD> serche how moche people of his party ther was slayne / And ther were founde but lytel past two honderd men slayne and viij knyȝtes of the table round in their pauelions<!--Prior quote:Thenne the kyng <WSD>lete</WSD> serche how moche people of his party ther was slayne.--> 
Meaning of the word marked with <WSD> tags:  To cause (+ bare infinitive).