Falkirk has a long history, going back at least to the Roman era. When the Antonine Wall was built across Scotland, it passed through what is now Falkirk. References to ‘Fawkirk’, 'Faukirk' and ‘Falkirk’ appeared before the end of the medieval period, but prior to this the place was usually called Egglesbreth, or variations of this (Gaelic: Eglais Bhris or Eglais Bhrec), with the church, itself, referred to as Varia Capella (thought to mean ‘speckled church').

In 1164, the church of ‘Eglesbrich’ and its lands were granted to the Augustinians of Holyrood Abbey in Edinburgh by the pope. Whether this grant was initially effective is uncertain, but in 1166 the bishop of St Andrews confirmed the possession of ‘Eiglesbrec’ to the Holyrood canons. It was at this time that the use of ‘Varia Capella’ first appears. Along with many other churches in the diocese, David de Bernham, bishop of St Andrews, dedicated the church in 1242 ('Eccl. que vocatur Varia capella, eodem anno pridie Id. Junij'). Just three years later, a perpetual vicarage was established at Falkirk, with a stipend of 10 marks attached to it. In the papal rolls of 1274-5, the church was assessed at 2 marks 6s 8d.

In the late 13th century, the name ‘Varia Capella' for the church of ‘Eglisbrich’ began to be less commonly used. In 1390 one hears of the church of ‘Faukirk’ in the Exchequer Rolls and in 1458 the area is called the ‘dominium of Falkirk’ in the Register of the Privy Seal. An attempt was made to make St Modan’s into a collegiate church in the mid-15th century, but in 1470 King James III of Scotland secured papal confirmation that only Holyrood canons would be able to serve the vicarage of Falkirk. At the same time, the vicarage was valued at £67 13s 4d. In 1533, another charter of the Great Seal refers to, ‘infra ecclesiam Variae Capellae’, while in the same charter is recorded a person who lives ‘in Villa de Fawkirk’. The name Fawkirk appears to mean ‘church at, or on the wall, or the boundary-line’, a name likely to refer to its proximity to the Roman Wall of Antonius.

The identification of the St Modan commerated at Falkirk is uncertain, as more than one saint with this name are known. Although the Aberdeen Breviary states a specific one for Falkirk, it has been argued by some that the early-16th century Breviary conflated two different St Modans.