<P> The explanation for the green and red colours that make up the background field arose during the Estado Novo period, the nationalist authoritarian regime that held power from 1933 to 1974 . It claims that the green represented the hope of the Portuguese people, while the red represented the blood of those who died serving the nation . Sources believe these noble meanings are far from the truth and are nothing more than propaganda, to provide an honourable justification to their choice . </P> <P> Despite the fact that these colours never constituted a major part of the national flag until 1910, they were present in several historical banners during important periods . King John I included a green Aviz cross on the red bordure of his banner . The red cross of the Order of Christ was used over a white field as a naval pennon during the Discoveries and frequently on ship sails . A green background version was a popular standard of the rebellious during the 1640 revolution that restored Portugal's independence from Spain . There are no registered sources to confirm that this was the origin of the republican colours . Another explanation gives full credit to the flag that was hoisted on the balcony of Porto's city hall during the 1891 insurrection . It consisted of a red field bearing a green disc and the inscription Centro Democrático Federal "15 de Novembro" (English: Federal Democratic Centre "15 of November"), representing one of many masonry - inspired republican clubs . Over the following 20 years, the red - and - green was present on every republican item in Portugal . The 1891 flag - inherited red stands for the colour of the republican - inspired masonry - backed revolutionaries, whereas green was the colour Auguste Comte had destined to be present in the flags of positivist nations, an ideal incorporated into the republican political matrix . </P> <P> The armillary sphere was an important astronomical and navigational instrument for the Portuguese sailors who ventured into unknown seas during the Age of Discoveries . It was introduced by the Knights Templar, whose knowledge was essential to the Portuguese Discoveries--Henry, the Navigator, the person mainly responsible for the development of Age of Discovery was actually the Grand Master of the Order of Christ . It thus became the symbol of the most important period of the nation--the Portuguese discoveries . In light of this, King Manuel I, who ruled during this period, incorporated the armillary sphere into his personal banner . It was simultaneously used as the ensign of ships plying the route between the metropolis and Brazil, thus becoming a colonial symbol and a fulcral element of the flags of the future Brazilian kingdom and empire . </P> <P> Adding to the sphere's significance was its common use on every Manueline - influenced architectural work, where it is one of the major stylistic elements, as seen on the Jerónimos Monastery and Belém Tower . </P>

What does the symbol on the portuguese flag mean
find me the text answering this question