Originally a bishop would entrust a priest with the 'cure of souls' (pastoral ministry) of a parish. When, in medieval Europe, this included the legal freehold of church land in the parish, the parish priest was the perpetual curate (curatus perpetuus). Occasionally a bishop might appoint a temporary or assistant curate (curatus temporalis). This was particularly the case if the perpetual curate was absent or needed assistance.
As the church became more embedded into the fabric of feudal Europe, various other titles often supplanted 'Curate' for the senior parish priest. 'Rector' was the title given to a priest in possession of the tithe income. This right to the income was known as a 'Living'. The title of rector comes from regere – 'to rule'. Those parishes where a monastery had appropriated the rights to the title income, a portion of this income was set aside for a priest to occupy the parish, essentially acting on behalf of the monastery, in other words vicariously – hence 'vicar'. In some cases, a portion of a tithe for a vicar could exceed the income of some rectors, depending on the value of the livings being compared.
In England and Wales, when a new parish was created from a larger rectoral or vicarious parish, the incumbent, or parish priest was sometimes styled as the Perpetual Curate. The term 'parson' came to be used to refer to all perpetual curates whether or not they received the higher titles of 'vicar' or 'rector'. This led to those perpetual curates who had no higher title preferring to be styled 'parson' so as to distinguish themselves from assistant curates. This happened to the extent that the term 'curate' came to mean 'assistant curate'. The British Parliament passed an act in 1868 which authorised all perpetual curates to use the title 'vicar'. This reinforced the notion that a curate is an assistant parish priest or deacon. Although widely called 'curates', however, they are still legally assistant curates. This English usage is used throughout the Anglican Communion and in some English-speaking Roman Catholic churches. The house provided for an assistant curate is sometimes colloquially referred to as a curatage.
Sometimes temporary curates, who have the status of assistant curates but lead the ministry of a parish, are appointed. However, to distinguish them from assistant curates, they are often referred to as 'priests in charge'. In the Church of Ireland temporary curates are called 'bishop's curates'.
The Book of Common Prayer (1662) of the Church of England refers to the clergy as 'bishops and curates' in the text of prayer of intercession for Holy Communion. It uses the word 'curate' in its original sense to refer to all clergy entrusted with a cure of souls and not just to assistant curates.
In the charismatic and / or evangelical parts of the Anglican church, the role of the curate is usually perceived a little differently. Curates in charismatic and / or Evangelical churches tend to be seen as an assistant leader to the overall leader, often in a larger team of pastoral leaders. Many of the larger charismatic / evangelical churches have sizeable staff teams with a number of pastoral leaders, some ordained and others who are not.
In modern Roman Catholic practice in the United States, 'curate' is the term popularly used for priests assigned to a parish who are not the pastor. The parochus, or parish priest or 'pastor' is the priest who has canonical responsibility for the parish. In canon law, he may be assisted by one or more 'parochial vicars', priests assigned to assist him - though incorrect these parochial vicars are popularly called 'curate', 'associate pastor' or 'assistant pastor' in various regions of the country.