Here's what I found on a Secular Franciscan Fraternity website:

The Franciscan Crown (or Seraphic Rosary)

The Franciscan historian Luke Wadding (1588-1657) dates the origin of the Franciscan Crown to the year 1422. He tells the story of a young novice in the Franciscan Order who, previously accustomed to express his devotion to the Blessed Virgin by adorning her statue with a wreath of fresh flowers; he was prevented from continuing this practice in the novitiate. In distress, he considered leaving the Order, but the Blessed Virgin appeared to him and instructed him to recite a Rosary of seven decades in honor of her seven joys; thus, he might weave a crown more pleasing to her than flowers on her statue.

From that time the practice of reciting the crown of the seven joys became a general custom in the order. Thus it became known as the Franciscan Crown or the Seraphic Rosary. Here are the Seven Joys of Mary:

1. The Annunciation
2. The Visitation
3. The Nativity
4. The Adoration by the Magi
5. The Finding of Our Lord in the Temple
6. The Resurrection
7. The Assumption of the Blessed Virgin into Heaven and Her Coronation as Queen of Heaven

Here is New Advent's write-up on it.

This devotion was originated in the thirteenth century. It recalls the Sorrows the Virgin Mother of God endured in compassion for the suffering and death of her Divine Son.

The Seven Sorrows Rosary consists of seven Hail Mary's, one for each of the seven Sorrows. One Our Father is said before each group of seven Hail Mary's: which is separated by a medal. On the three beads of the rosary, at the end, three Hail Mary's are said in honor of the Tears of Our Sorrowful Mother. While reciting the prayers one meditates on the Seven Sorrows of Mary:

1. The prophecy of Simeon
2. The flight into Egypt
3. The loss of the Holy Child, Jesus, at Jerusalem
4. The meeting of Jesus on his way to Calvary
5. The standing at the foot of the Cross
6. Jesus being taken from the Cross
7. The burial of Christ
   

Here is New Advent's write-up on it.