another possibility is that there were distubances out beyond the outer planets that brought gangs of comets into the inner solar system. ancient men might have noticed that these comets came and went in the night sky at regular intervals.
http://abob.libs.uga.edu/bobk/ccc/cc072798.html
(4) NEW IMPLICATIONS FOR A TAURID METEOROID SWARM
D.J. Asher*) and K. Izumi: Meteor observations in Japan: New
implications for a Taurid meteoroid swarm. MONTHLY NOTICES OF THE
ROYAL ASTRONOMICAL SOCIETY, 1998, Vol.297, No.1, pp.23-27
*) COMMUN RES LABS, 893-1 HIRAI, KASHIMA, IBARAKI 3140012, JAPAN
Observational evidence is sought that the long-term (10(4) yr) action
of a mean motion resonance with Jupiter can produce structure in a
meteoroid stream, concentrating meteoroids in a dense swarm. More
specifically, predictions tabulated by Asher & Clube of enhanced
meteor and fireball activity from a Taurid Complex swarm in the 7:2
resonance are compared with observational data collected in Japan
over several decades. The swarm model was proposed for reasons
independent of the observations analysed here, and these newly
considered data are shown to be consistent with it. This allows
increased confidence in the Taurid swarm theory, and more generally
could mean that resonant trapping is a dynamical mechanism affecting
a significant amount of meteoroidal material in the inner Solar
system.