Their story
No one knows when they lived.
Their Life says they were brothers and stonemasons in Illyria, who learned their craft and their faith from two Christians, Proclus and Maximus. The governor Likaion sent them to build a pagan temple, and while they worked a chip of stone struck the pagan priest’s son in the eye; the brothers prayed for him, his eye was healed, and he and his father came to believe in Christ. When the temple was finished, the brothers gathered the Christians, smashed the idols and set up the Cross in it. The governor had them thrown down an empty well and covered with earth, and years later their relics were found whole and taken to Constantinople.
Martyrs Florus and Laurus of Illyria, Orthodox Church in America; The Roman Martyrology, 1916, 18 August
Their feast day
18 August: Their feast in the Catholic Church and in the Orthodox churches on the new calendar. Those on the old calendar keep it on 31 August.
The Roman Martyrology, 1916, 18 August; Martyrs Florus and Laurus, 18 August, Orthodox Church in America
Why people ask Sts Florus and Laurus
Animals and pets
They are the patrons of horses, and a plague among horses is said to have ended when their relics came to Constantinople. An Orthodox cathedral in America blesses animals on their feast, 18 August.
Where it comes from
Who wrote it
This hymn to them is in the Russian book of services for 18 August. No one knows who wrote it or when.
In Church Slavonic
Преудо́бренную и Богому́друю дво́ицу пресве́тлуювосхва́лим, ве́рнии, по достоя́нию,Фло́ра преблаже́ннаго и Ла́вра всечестна́го,
и́же усе́рдно Тро́ицу несозда́нную я́сно пропове́дасте всем,те́мже пострада́вше до кро́ве,и венцы́ пресве́тлыми увязо́стеся,
моли́теся Христу́ Бо́гу, да спасе́т ду́ши на́ша.
From Минея, август (Moscow, 2002), 18 August, as printed by Azbyka.