From the Celtic invasions of the fourth century, B.C., until its union with England in 1800, Ireland developed its own distinctive Celtic culture. Its Christian religion, language and literature, law, social structure and land system were of Celtic origin and different from neighboring England's. Almost twelve hundred years of independence allowed Ireland to establish its unique qualities and become recognized as a nation. Then came three hundred years of English occupation and desultory control followed by two hundred and fifty more years of English conquest, confiscation and disruptive colonization. Finally came almost one hundred years of English economic subjugation and suppressed Irish indignation until nationalist Ireland in revolt was made a part of frightened England in 1800. The years of independence produced a unique cultural tradition which English strength changed but could not extinguish. What remained in 1800, supported by an irrepressible demand for national independence, was Ireland's Celtic tradition.