Can someone explain to me in great detail how the practice of granting indulgences came about? I have heard less than great things about them in history books at school (not the best source, I know) and although I know these are okay, I don’t know how to put into words why they’re a practice in the church. Thanks.
Don’t listen to the anti-catholic garbage they taught us in history class. It’s anti-catholic masons or protestants(yes, I consider freemasons a cult group) who author these…
This is a great site explaining indulgences in detail: fisheaters.com/indulgences.html
Oh please.
Back in the earliest days of the Church, penances lasted for years on end. For example, St. Margaret of Cortona gave birth to a child out of wedlock, and was required by her Confessor to give the child up for adoption, and to go around in sack-cloth and ashes, begging for alms, until the child’s 18th birthday.
As time went on and more and more people became Christians, and especially after it became legal to be a Christian after 317 AD, these long penances placed a burden on society as a whole - you could not have these large numbers of people homeless and going around begging every time they confessed a moral sin, so the Church instituted a system of Indulgences, where the reciting of certain prayers or doing certain good deeds, or going on certain pilgrimages would suffice to replace either all or some portion of these years-long penances.
In the old days, they actually specified how many years of penance the partial Indulgences would replace, but since people began to think that they were actually getting that amount of time off of Purgatory, that practice has stopped, and we now refer to “partial” and “plenary” Indulgences.
Thanks for the link. I love fisheaters!! 
Indulgences are wonderful, but we have to remember without them the penance due would be quite extraordinary to many modern eyes, for our sins – which shows how serious sin is. And we still have to do some penance even without them. 
The Catechism (and footnotes) may be of help, see paragraphs 1471-1478.