Digha Nikaya (Coleção dos Discursos Longos) 1:162
SUJATOSeyyathāpi, bhante, rañño paccantimaṁ nagaraṁ daḷhuddhāpaṁ daḷhapākāratoraṇaṁ ekadvāraṁ,
Suppose there was a king’s frontier citadel with fortified embankments, ramparts, and arches, and a single gate.