Complex sentence: A colony of North Australia existed briefly after it was authorised of a letters patent of 17 February 1846 which included all land in the Northern Territory and the present state of Queensland lying north of 26ºS.
Split into simpler sentences: A colony of North Australia existed briefly after it was authorised by letters patent of 17 February 1846. The colony comprised all land in the Northern Territory and the present state of Queensland lying north of 26ºS.