Complex sentence: Construction of the Althorpe Island lighthouse began in 1877, and it was operated and maintained by resident lighthouse keepers from its first light in 1879 until it was demanned in 1991.
Split into simpler sentences: Construction of the Althorpe Island lighthouse began in 1877. Once complete, the lighthouse was operated and maintained by resident keepers from its first light in 1879 until it was demanned in 1991.