Livy

Cloelia was one of the hostages demanded by Lars Porsinna for withdrawing his troops from the Janiculum, during the seige of Rome in 508 B.C.

Ergo ita honorata virtute, feminae quoque ad publica decora excitatae, et 
Cloelia virgo, una ex obsidibus, cum castra Etruscorum forte haud procul 
ripa Tiberis locata essent, frustrata custodes, dux agminis virginum inter 
tela hostium Tiberim tranavit sospitesque omnes Romam ad propinquos 
restituit. Quod ubi regi nuntiatum est, primo incensus ira oratores Romam 
misit ad Cloeliam obsidem deposcendam: alias haud magni facere; 
deinde in admirationem versus supra Coclites Muciosque dicere id 
facinus esse, et prae se ferre quemadmodum, si non dedatur obses, pro 
rupto foedus se habiturum, sic deditam intactam inviolatamque ad suos 
remissurum. 

1 honorata virtute ablative absolute referring to honors given to Mucius for his bravery.
quoque also, too
2 obses/opses, obsidis, m., f. hostage 
* forte by chance 
3 frustror (1 depon.) deceive, trick
custos, custodis, m. guard
4 trano (1) swim across
sospes, sospitis (adj.) safe and sound, unhurt
propinqui relatives
5 oratores ambassadors  
regi Lars Porsinna, the Etruscan king
6 magni genitive of value/price
7 Coclites Muciosque, heroic men whose stories are told in chapters 10-13
8 * prae se ferre to display, make known
quemadmodum how
dedo give back dedatur subjunctive in subordinate clause in indirect statement
8-9 pro rupto as broken
9 * habeo have, hold, consider

Utrimque constitit fides: et Romani pignus pacis ex foedere restituerunt, 
et apud regem Etruscum non tuta solum sed honorata etiam virtus fuit, 
laudatamque virginem parte obsidum se donare dixit; ipsa quos vellet 
legeret. Productis omnibus elegisse impubes dicitur, quod et virginitati 
decorum et consensu obsidum ipsorum probabile erat eam aetatem 
potissimum liberari ab hoste quae maxime opportuna iniuriae esset. Pace 
redintegrata Romani novam in femina virtutem novo genere honoris, 
statua equestri, donavere: in summa Sacra via fuit posita virgo insidens 
equo.

11 utrimque on both sides
* consisto -ere, constiti stand firm constitit (it) was kept
pignus, n. pledge  
ex foedere in accordance with the treaty 
12 * non solum … sed etiam not only … but also 
13 *dono (1) present (someone acc., with abl.)
se subject of donare 
14 impubes (adj.) youthful; as a noun young 
14-16 As a modest young woman it was seemly for Cloelia to choose the very young hostages (rather than grown up young men). The younger children were also in greater danger of being molested.
15 probabilis, -e likely, acceptable, approved  
16 potissimum especially 
opportunus suitable, exposed