There have been carvings of this ancient symbol found in Bronze-age burial urns dating back as far as 1400 BC. Although it's been used in many cultures, the cross eventually became identified with Christianity and the crucifix.
The Solar Cross symbol is a variation on the popular four-armed cross. It represents not only the sun, but also the cyclical nature of the four seasons and the four classical elements.
The concept of sun worship is one nearly as old as mankind itself. In early communities that were primarily agricultural, and dependant on the sun for life and food and drink, it is no surprise that the sun was regarded as a God and worshipped.
Because of its association with the Sun itself, this symbol is typically connected to the element of Fire. You can use it in ritual workings that honour the sun or the power, heat and energy of flames. Fire is a purifying energy, but can also destroy. It also creates, and represents the fertility and masculinity of the God. You can use this symbol in rituals that involve casting away the old, and rebirthing the new, or for celebrations of the solstices.