It is difficult to grasp nowadays how the ordinary parishioner was influenced by canon (Church) law in the Middle Ages. Today we have a Code of Canon Law which mainly affects clergy and religious. Except in matters of marriage, laity are not often made conscious of Canon Law.
If we take the year 1300, there was no book containing all Church law but there were many compilations of decrees of Ecumenical Councils, synods, and popes. These often spelt out in detail the many obligations of a layman. Here are some.
In the parish church, the layman had to attend Mass on Sundays and, after 1215, receive Communion once a year, confess to the parish priest and have his children baptised. So parish boundaries were important and would be marked out from time to time.
Canon law reserved all cases involving clergy to the jurisdiction of Church courts. Here the definition of "clergy" was wide: obviously priests, deacons, those in minor orders and religious but also those we would classify as laity, such as university and grammar school students. The greatest volume of business was done with clergy (thus defined), involving hundreds of Church corporations.
All matters of testaments and wills and the granting of probate were also encompassed. Most wills were made orally, so proof of a will involved taking an oath, that is, calling on God as a witness, hence a matter for the Church. This jurisdiction lasted well beyond the Reformation, for example, in England the Courts Christian handled probate of wills up to 1887 as well as matters of perjury, oaths and contracts.
All matters of matrimony were a concern of the Church, e.g., marriage and separation, and the legitimation of children, which were very important in those times for inheritance. Other aspects included sexual offences, such as adultery and fornication.
Especially important was the matter of payment of tithes (tenths). Early in the history of the Church, rulers and bishops decided that everyone had an obligation to support the Church financially. They found a model in the Old Testament where the payment of one-tenth of income to Levites and the Temple was made obligatory.
During the Middle Ages, most income came from agriculture, so most landowners and tenants had to pay tithe. The amount of tithe actually varied, with grain, animals, wine, oil, timber, hay, even garden herbs, being collected and deposited in large barns in many places. Tithe was also exacted from artisans and tradesmen, and from bakers, brewers and fishermen who were required to pay a tenth of their profits. The parish priest received some of this and in addition he was allotted his own land for farming.
This system generated work for scores of lawyers who had to determine the rules. If sheep were kept on one property in winter and on someone else's property in summer, who had to pay the tithe? No need to worry - lawyers soon worked out in detail who was responsible.
This transfer of income developed into a huge business.
Church corporations, e.g., monasteries, nunneries, cathedrals, received tithes with the rights to tithes often traded. A monastery might own the right to tithes of 50 parishes and in a large monastery, several monks might do little else but collect tithe and ensure its housing and distribution.
Tithes were diverted to laymen, to lords of manors, to popes, to universities and to parish priests who did not reside in their parishes but appointed a vicar at a low salary to perform priestly duties. Absenteeism was condemned by synods and councils and popes, with about as much success as prohibition in the USA in the 1920s. Cardinal Wolsey (1473-1530) was Archbishop of York, drew revenues from the diocese, yet never set foot in it as bishop.
It is important to note that payment was compulsory. Penalties for failure to pay included fines, seizure of farm animals, destruction of homes, and imprisonment. In 1261, a Lambeth Council required every bishop to provide one or two prisons in his diocese. Other penalties included cursing and excommunication.
Today excommunication involves exclusion from various offices and from receiving Communion but in earlier times the excommunicated could not defend themselves in courts or inherit property or make a will. If the crime was heresy, they could be executed by the secular authorities.
Enforcers of canon law in England were called Summoners who had at their disposal armed men, whose duties were similar to those of our enforcers in the Australian Taxation Office. After all, if you fail to pay taxes your property could be taken from you and yourself be taken to jail by armed men.
The Friar's Tale from Chaucer's Canterbury Tales succinctly captures the Summoner's task:
Who boldly did the execution due
On fornication and on witchcraft too
Bawdry, adultery, and defamation,
Breaches of wills and contract, spoliation
Of church endowment, failure in the rents
And tithes and disregarded sacraments.
All these and many other types of crime
That need have no rehearsal at this time,
Usury, simony too.
We should not think that this system of tithing died with the end of the Middle Ages. It remained in a various forms in most nations in Europe, including Russia, well into the 19th century. It was abolished in England in 1837, yet remained in operation in Quebec.
How strange all this seems. To understand it we have to remember that life was so precarious. Most people highly valued eternal salvation and were willing to pay for the means to help themselves achieve it.
Despite the sometimes crude operations of canon law, people came to believe in their Saviour and found alleviation from deep anxieties through their membership of the Church which they willingly supported.