After the Downfall by Harry Turtledove

fancy dress who wore a gold circlet with ball-topped knobs sticking up from it.
    He did have an impressive bass rumble. Aderno’s lighter voice turned his words into ones that made sense to Hasso: “You did us a service. I hope you will take service with us. I have heard you know fighting tricks we would all do well to learn, and I have also heard the power dwells in you.”
    Hasso started to say he didn’t know anything about the power. At the last second, he clamped down on that. The less he gave away, the better off he was likely to stay. And so all that came out was, “I’ll be happy to join you, your Majesty.”
    After the wizard turned that into Lenello, King Bottero’s ice-blue eyes suddenly twinkled. A grin pulled up the outer corners of his mouth. He set a massive hand on Hasso’s shoulder and said something in what could only be a man-to-man tone. Hasso figured out the likely translation even before Aderno gave it: “I’ll bet you will. She’s quite a woman, isn’t she?”
    “Yes, your Majesty.” Hasso could say that in Lenello. He would have meant it no matter what language he used. Then he eyed the king’s roguish expression in a different way. Was he imagining things, or did Bottero sound as if he knew exactly what he was talking about?
    The Wehrmacht officer didn’t see any polite way to ask the king. Maybe he would be able to find a polite way to ask Velona. Or maybe he didn’t want to know.
    Then Bottero spoke again, and Hasso found out whether he wanted to or not. “His Majesty makes himself remember you are a foreigner, and so you are not used to our ways,” Aderno said. He waited for Hasso to nod, then went on, “He will borrow the goddess for the coming summer solstice, as he does each solstice and equinox. No doubt, he says, you have some such customs in your own land.”
    “No doubt,” Hasso said tonelessly. He’d heard of pagan fertility rites, but he’d never dreamt they might matter to him. And what the hell was he supposed to say when the king told him, Hey, I’m going to borrow your girlfriend for a night? If he said, No, you’re not, chances were he’d be shorter by a head. And if he said no to Velona, she was liable to laugh at him. If she was the goddess on earth, wasn’t this part of her job requirement?
    “You don’t say much,” King Bottero observed through Aderno. He might be the size of a draft horse, but he was no dummy.
    “What am I supposed to say?” Hasso made himself shrug. “If it doesn’t bother Velona, how can I squawk?”
    Bottero laughed when he heard that. “I knew you were a sensible fellow,” he said, and gave Hasso a slap on the back that almost knocked him sprawling. “When you get right down to it, the women do the deciding.”
    “ Ja ,” Hasso agreed with a crooked smile. Pagan fertility rites or not, this world and the one he’d escaped weren’t so very different. He turned to Aderno. “If I take service here, I know whose service I’m joining. Who’s on the other side?”
    “A wise question. You should always know your foes at least as well as your friends,” the wizard said. The Wehrmacht officer grunted. Hitler should have thought about that before he got into a war against both the USA and the USSR. If the Führer had, Hasso wouldn’t have been standing here right now. Aderno went on, “You would serve his Majesty against the other Lenello kingdoms, except the ones that are allies.”
    Hasso nodded. “That makes sense.”
    But Aderno wasn’t done. “And you would serve him in ensuring that the Grenye in his kingdom know their place - know it and keep it.”
    “Fair enough.” If you were going to rule people you’d conquered, they had to respect you. Hasso had seen that in Russia. Let them think they were as good as you were and there’d be hell to pay. The Germans had paid it, too.
    “And” - now Aderno seemed like someone holding his nose against a bad smell that wouldn’t go away “there is Bucovin.” When