This feast, like many others, was local before it was placed in the Roman calendar.... Paul V placed it (27 September, 1608) among the feasts of the general calendar as a double "ad libitum" (Bäumer, op. cit., II, 277)....At the request of Ferdinand of Austria, afterwards emperor, he made them obligatory in all regions subject to the Imperial power; to all other places he conceded them ad libitum, to be celebrated on the first available day after the Feast of the Dedication of St. Michael the Archangel. It is believed that the new feast was intended to be a kind of supplement to the Feast of St. Michael, since the Church honoured on that day (29 September) the memory of all the angels as well as the memory of St. Michael.... Among the numerous changes made in the calendar by Clement X was the elevation of the Feast of Guardian Angels to the rank of an obligatory double for the whole Church to be kept on 2 October, this being the first unoccupied day after the feast of St. Michael....Finally Leo XIII (5 April, 1883) favoured this feast to the extent of raising it to the rank of a double major.The following is an old English bed-time prayer for children, of which there are many variations:
Matthew, Mark, Luke, and John,Needless to say, the belief in angel guardians is of ancient origin and has a strong Biblical foundation, as the Book of Exodus bears witness:
Bless this bed that I lay on.
Before I lay me down to sleep,
I give my soul to Christ to keep.
Four corners to my bed,
Four angels 'round my head,
One to watch, one to pray,
And two to bear my soul away.
I go by sea, I go by land,
The Lord made me with his right hand,
If any danger come to me,
Sweet Jesus Christ, deliver me.
For he's the branch and I'm the flower,
Pray God send me a happy hour,
And if I die before I wake,
I pray the Lord my soul to take.
20 Behold I will send my angel, who shall go before thee, and keep thee in thy journey, and bring thee into the place that I have prepared. 21 Take notice of him, and hear his voice, and do not think him one to be contemned: for he will not forgive when thou hast sinned, and my name is in him. 22 But if thou wilt hear his voice, and do all that I speak, I will be an enemy to thy enemies, and will afflict them that afflict thee. 23 And my angel shall go before thee.... (Exodus 23:20-23)Recta Ratio has some pictures and some thoughts as well. More HERE.