From early times the church commemorated its great leaders and heroes, especially those who had suffered martyrdom, by observing the dates of their death. This gave rise to the sanctoral section of the liturgical calendar, and it was customary for those churches whose members had included great Christians or martyrs to gather for a Communion service at the martyr's tomb, which was sometimes used as a Communion table. At a later stage churches were built over these sites, and thus began the practice of dedicating churches in honor of specific saints.
Because there were other Christians whose faith and service (and even martyrdom) went unrecorded, and because some centers of the church gained more martyrs than could be commemorated in the days of the year, the practice of a general commemoration on All Saints Day developed. Originally celebrated on May 13, this festival was transferred in 835 to November 1, and medieval ideas of purgatory led to the following day being observed as All Souls Day, when the souls in purgatory were remembered.
At the Reformation the latter festival was dropped. Reformed churches use All Saints Day to thank God for the faithful departed.
I think this is rather interesting, because I don't recall ever hearing about All Saints Day in any of the churches I've been a part of. But most of them make a big deal out of Veterans Day every year. I guess it just makes me kind of wonder - what does that say about us as Christians that we make a bigger deal over those who have given their lives for country, rather than those who have given their lives for Christ? Not that I have anything against veterans, but which is more important to us: Christ or country?
We will be celebrating a communion toast to the saints this Sunday, and I will be preaching on the subject.