[Sidenote: Herero tradition of the origin of men and cattle from the sacred _omumborombonga_ tree.] The Herero have a tradition that in the beginning they and their cattle and all four-footed beasts came forth from the _omumborombonga_ tree in a single day, whereas birds, fish, and creeping things sprang from the rain. However, slightly different versions of the Herero genesis appear to be current. As to the origin of men and cattle from the tree, public opinion is unanimous; but some dissenters hold that sheep and perhaps goats, but certainly sheep, issued from a flat rock in the north of the country. For some time past, unfortunately, the tree has ceased to be prolific; it is of no use waiting beside it in the hope of capturing such oxen and sheep as it might bear. Yet still the Herero testify great respect for the tree which they regard as their ancestor (_omukuru_). To injure it is deemed a sacrilege which the ancestor will punish sooner or later. In passing it they bow reverently and stick a bunch of green twigs or grass into the trunk or throw it down at the foot. They address the tree, saying, “_U-zera tate mukururume_, Thou art holy, grandfather!” and they even enter into conversation with it, giving the answers themselves in a changed voice. They hardly dare to sit down in its shadow. All this reverence they display for every tree of the species.[717] [Sidenote: Migration from one country to another sometimes involves a change of sacred tree.] On the whole, then, we may infer that so long as the Herero dwelt in a land where their ancestral tree abounded, they made the male fire-stick from its wood; but that as they gradually migrated from a region of tropical rains and luxuriant forests to the arid mountains, open grass lands, and dry torrid climate of their present country,[718] they had in some places to forgo its use and to take another tree in its stead. Similarly the Aryan invaders of Greece and Italy were obliged, under a southern sky, to seek substitutes for the sacred oak of their old northern home; and more and more, as time went on and the deciduous woods retreated up the mountain slopes, they found what they sought in the laurel, the olive, and the vine. Zeus himself had to put up with the white poplar at his great sanctuary of Olympia in the hot lowlands of Elis;[719] and on summer days, when the light leaves of the poplar hardly stirred in the languid air and the buzz of the flies was more than usually exasperating, he perhaps looked wistfully away to the Arcadian mountains, looming blue in the distance through a haze of heat, and sighed for the shadow and the coolness of their oak woods.