Trajan (r. 98-117) established the first all-camel cavalry unit, the Ala I Ulpia dromedariorum Palmyrenorum.

The turma was still commanded by a decurio, aided by two subaltern principales (under-officers), a sesquiplicarius (soldier with one-and-a-half times pay) and a duplicarius (soldier with double pay), as well as a signifer or vexillarius (a standard-bearer, cf. vexillum).