Porém, se acaba o sol, porque nascia? Se formosa a luz é, porque não dura? Como a belleza assim se trasfigura? Como o gosto, da pena assim se fia? Mas no sol, e na luz, falte a firmeza, Na formosura não se da constancia, E na alegria, sinta-se a tristeza. Comece o mundo, emfim, pela ignorancia; Pois tem qualquer dos bens, por natureza, A firmeza somente na inconstancia.[21] IV The first half of the eighteenth century, a review of which brings our first period to a close, is the era of the _bandeirantes_ in Brazilian history and of the Academies in the national literature. The external enemies had been fought off the outer boundaries in the preceding century; now had come the time for the conquest of the interior.[22] The _bandeirantes_ were so called from _bandeira_, signifying a band; the earliest expeditions into the hinterland were called _entradas_, and it is only when the exploring caravans grew more numerous and organized that the historic name _bandeirantes_ was bestowed. Men and women of all ages, together with the necessary animals, composed these moving outposts of conquest. This was a living epic; the difficulties were all but insurmountable and the heroism truly superhuman. No literature this,--with its law of the jungle which is no law,--with its immitigable cruelty to resisting indigenous tribes, and finally, the internecine strife born of partial failure, envy and vindictiveness.