from about 1939 walsh concerned himself with the medieval irish annals and annalistic dating. an especially valuable study, "the dating of the irish annals", was published shortly after his death. world war ii brought an unexpected boon in the relocation of the first half of the annals of the four masters from dublin to multyfarnham. these two autographs had been held at stowe house and rome until their return to ireland in 1872, after which they had been kept at the franciscan house at merchant's quay, dublin. this meant that john o'donovan's edition relied on two 18th century copies and thus contained some defects. paul walsh availed of this opportunity and by the time of his own death had transcribed the years ad 428 through to 1170, totalling 650 pages.