There is a distinction in Catholicism on this point. The attribution of "worship" regarding Catholic practice and saints is usually derogatory and is said as an insult. Within Catholicism the term "veneration" (or dulia) is used rather than "worship" or "adoration" (latria)--which is reserved for God.

I will assume that you did not mean to offend, but in the future just be aware that language choice on this issue can avoid needless confrontations.

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There is a history of the conception of saints, as well as how or if they are to be honored. However, I am not qualified to give you that history in a forum such as this.

This is a really complicated question. People in western civilizations have been worshipping, praising, venerating, and memorializing dead people as far back as we have records. But for Christians, it stems from their ultimate dead guy who conquered death, Christ. From there, it stems naturally to his disciples, his family, and their followers, the early Christian martyrs who died under Roman persecution, the early Church and desert fathers who were the first big push in the Christian intellectual tradition, and so and so on. It makes sense that you praise your main religious figure, but what do you do with other guys (and gals, especially Mary) who you also think are really awesome in your religious tradition?

Eventually, places wanted their own holy men and women to show how awesome their Christian tradition was, so they began recording remarkable events, establishing traditions, and writing biographies of people they saw as particularly holy. This type of literature is called, generally, hagiography. Each region has its own traditions, saints, and cults (not the modern meaning) that help creat and promote its particular set of holy people -- who are not all necessarily considered saints by the head church in Rome. Again, this is an incredibly complex issue that has a rich and interesting history and cannot be adequately answered in this format, or even in a few books. If you want a couple of particularly interesting figures in this tradition, look up anything on Mary (the mother of Christ), the cult of Thomas Becket, and Martin of Tours.

Just a point of semantics, in general, people in the medieval Christian tradition prayed to saints not for their direct help, but for them to intercede on their behalf with God and Christ. For example, St. Edmund the Martyr is said to have answered the prayers of the English when he brought divine justice upon Swein Forkbeard by striking him down after Swein had burned down a lot of churches and killed a bunch of good Christians. Edmund acted both as God's agent and an agent of the people, exacting divine judgment on someone who grievously sinned against God's will (i.e. killing Christians and burning churches), and providing aid to those who had proved themselves good Christians through prayer, donations, etc.

Here are a few places you can start your investigation:

Caroline Walker Bynum. Jesus as Mother (1984)

Thomas Head. Medieval Hagiography: An Anthology (2001)

Michael Goodich. Lives and miracles of the saints: Studies in Medieval Latin Hagiography (2004)

J. Howard-Johnston. The Cult of Saints in Late Antiquity and the Middle Ages (1999).

Hope this helps a little. Happy Reading!

I think I can address your question in the context of popular belief. In the early medieval period, people retained this sort of magical agrarian consciousness that was (in some places, until the mid 20th century!) common to all people whose entire lives are committed to agriculture which consequently shapes the way they viewed the world. To 'early' Europeans, the cycles of nature were not self evident, which required their participation in the cosmos; thus we hear of peasants from Germany to Italy shouting encouragements like "conquer, moon!" at the moon during a lunar eclipse, as they believed that the moon was struggling against monsters or sorcerers.

The pre-Christian agrarian believed that he/she lived in symbiosis with nature. They were made from the same elements as nature and could logically exert their own influence in its course through magic. Man is inseparable from nature and must exert his influence over it to make it function. Magic was an incredibly important aspect of life to the European agrarian; they applied it to every aspect of daily life and it served important social, philosophical and ceremonial roles as well. To the agrarian, magic was inseparable from social life, to the extent that clerics could never really define what pagans actually did because the social and spiritual were so inseparable in his worldview. With the conversion to Christianity, pagan belief as a systematic method of worship was rooted out or synthesized with Christian teachings, however this consciousness remained the same.

Now, before I sound like some old coot rambling on about magic, I'll make one more point about medieval popular consciousness before talking about saints. There was obviously a divide between the scholarly, theological worldview of the cleric and the primeval agrarian worldview which I have just described an aspect of. Another element of this worldview was what I call the principle of concreteness; those who inherited the agrarian consciousness for the most part rejected allegory or metaphor as narrative tools. These concepts were certainly understood by the clergy, but the peasantry rejected them in favour of the concrete, the real. We shall see how this ties into the Cult of Saints later.

So, I've established that magic and concreteness were essential components of the medieval agrarian worldview. But what on earth does magic or the rejection of allegory have to do with saints? I would argue that the popularity of saints was to an extent the result of their capacity to harness both of these aspects of the medieval popular worldview. Saints were the popular hero of medieval culture, a spiritual hero who replaced the corporal hero of pagan epics. Hagiography to some extent represents medieval popular culture because they were written with the agrarian peasantry in mind and consequently reflected some of their values and beliefs, but in the context of didactic teaching.

Saints in their stories commonly use what we might perceive as magic; killing wizards, making mills turn backwards, curing the incurable. Even after death, a saint could help his/her community, his bones or dust from his tomb had a sort of magical power. They were popularly perceived as magicians or sorcerers who could bring prosperity to those who venerated them or harm to those who spurned them. St. Remi is a notable example of a saint who harmed or killed those who disrespected him or questioned his holiness. Clerics used hagiography to demonstrate the power of faith and church; if you were a bad Christian or heretic, a saint would pop a cap in yo ass. Although the clergy used the cult of saints to inculcate proper Christian values, the Cult as an institution was the domain of the masses.

It is tempting to conclude that the people simply viewed them as continuations of pagan gods, but I don't believe this is the case. Medieval people venerated the saint because they filled the agrarian need for magic; it was a holy magic, condoned by the clergy and to an extent I believe that the veneration of saints was imposed on the church by its mass popularity. Saints also fulfilled the popular concept of concreteness; the saint was temporally and geographically nearer to the medieval peasant than an abstract and almost formless Christian God. Because they were corporal and easy to imagine, not to mention see (you could find saints' bones, hair, blood in churches across Europe!) they were more suited for the obsession of the masses because they displayed holy power in concrete form.

So this is all to say that the popularity of saints in the medieval ages originated in their ability to fulfill the magical and concrete expectations and worldview of the agrarian masses. The Cult of Saints was a sort of popular culture imposed on the church, but also used by it to show what good Christian values were to the peasantry.