Maryada Purushotham Ram
The word Ramayan has been derived from two words ram and ayan. Ram ramayate 1 means to remain engrossed in one’s target. It is with reference to remaining engrossed in Bliss which is derived from spiritual practice. In the quote “Samasya ayanam Ramayanam”2 “ayan” means speed, the path or to go. Hence Ramayan is that which leads one to, ‘The Supreme Lord’. In other words, King Rama or the Lord Rama as he is often addressed to shows the path to reach Moksha (which the ultimate Purushartha of all hindus) by example of his own life.
Among the pantheon of Hindu Gods and Goddesses and Avatars, Rama probably is the only God, who is worshiped all over India, not just worshipping, he is respected and revered all over India. Even in places like Gujarat where Krishna worship predominates or in West Bengal, where Kali worship predominates; the respect and the devotion which Hindus have in their minds for Rama is same as in other parts of the world. The reason for it is Lord Ram is considered an ‘Ideal Human’. His life is considered as ‘Ideal Life’. For this reason, Rama is referred as ‘Maryada Purushotham’ Rama, and his Kingdom, the ‘Ramarajya’ as the ideal state.
Rama belongs to the "Ikshvaagu Vamsaa", which starts with Lord Brahmma and Brahmma's son 'Mareechi' takes over the reigns and from him his son 'Kasyapaa', 'Vaivaswathaa', 'Manu', 'Ikshvaagu'. Then it goes on hereditarily to 'Manthaatha' to 'Bagiratha', then to 'Raghu' (hence the other name 'Raghu Vamsaa') to 'Yayaathi' to 'Ajan', the father of 'Dasaratha' from whom Lord Rama takes over the reigns.
Rama is considered an Ideal son, because he gave up his rightful claim to the throne, and agreed to go into exile for fourteen years, to fulfill the vow that his father had given to Kaikeyi, one of King Dashratha's wives. He is considered as Ideal Husband who practiced the Ideal of Monogamy even though polygamy was common practice among the Kshatriyas. Even after he banished Sita, he remained loyal to her and was doing penance with a gold statue of Sita. He was an Ideal Friend who helped Sugriv, Bibhishan, etc. during catastrophes in their lives. Most importantly Rama is an Ideal King who chose his ‘Raja Dharma’ over his ‘Pathi Dharma’ when he banished Sita because his subjects expressed doubts about the chastity of Sita, ignoring his personal relationship with her.
Rama may or may not be historical, but he represents the values, morals and ethics of Hindus. Rama is the symbolism of Dharma. In short Rama teaches the ideals of Sanatana Dharma by living life according to it. The unique position and importance Lord Ram has in the Hindu scheme of things is due to this position of being Maryada Purushotham.
1, 2 - http://www.hindujagruti.org/hinduism/knowledge/article/what-is-the-real-meaning-of-ramarajya.html#11