Tempi Present participle:
besieging
Present:
besiege (3.person: besieges)
Past:
besieged
Future:
will besiege
Present conditional:
would besiege
Present Perfect:
have besieged (3.person: has besieged)
Past Perfect:
had besieged
Future Perfect:
will have besieged
Past conditional:
would have besieged